The Baltic Sea is in many ways good for cruising on small craft. There are many towns worth seeing, an abundance of guest harbours – and large archipelagos with thousands and thousands of islands and islets. The Baltic is also a safe destination, with well organized societies, short distances, no typhoons and no tides. Finland and Sweden in the north have large inland archipelagos in addition to the coastal ones.
In the archipelagos and lakes you do not necessarily need a yacht. Although the coastal archipelagos and the biggest lakes are indeed big enough for any yacht, smaller boats or even a kayak offer a different experience.
Countries and territories
The countries of the Baltic Sea, clockwise from the Danish straits (links to country sections):
- Denmark has the Danish straits, the most usual entryway into the Baltic Sea. The Danish archipelago is a worthy boating destination by itself
- Sweden has great coastal archipelagos, a few bigger coastal islands and also three large lakes accessible via canals
- Finland has the autonomous demilitarized Åland archipelago and the Archipelago Sea of renowned beauty and complexity. The land of the thousand lakes also offers complex inland boating destinations.
- Russia's main attraction is Saint Petersburg, built 1703 as capital of the Russian Empire. Via the Neva you can reach the internal waterways of Russia. There is also the small Kaliningrad Oblast exclave between Poland and Lithuania.
- Estonia has very different look-and-feel from the Swedish and Finnish archipelagos, with bigger islands and sandy shores.
- Germany offers another entrypoint via the Kiel Canal. Its Baltic Coast is a popular tourist destination.
The Baltic Sea is connected to the Atlantic through the Danish straits (Little Belt, Great Belt and Øresund). These are not deep, so the Baltic gets salt water mainly by storms in the right circumstances every few years, while it gets fresh water from a large drainage basin; the water of the Baltic is brackish, with less than one percent salt in the surface water.
In wintertime the north parts of the Baltic are covered with sea ice, as are many bays in the south. In some winters ice covers most of the sea. The yachting season is mainly from May to September. In summer day temperatures are typically 15–25°C. Water is cool even in July, especially some distance from the shore.
The Baltic has no tides. The water level varies by wind and air pressure, with deviations of more than one metre being unusual. Severe storms are also seldom experienced, especially not in spring and summer. Winds are mostly light to moderate, from varying directions with westerly or southwesterly winds most common. Seas are seldom high, as they will develop at most over a day or two, and the swell will soon die out. In rough weather, however, the seas are quite sharp; gales should be taken seriously. Significant wave height of 7 m occurs every few years in parts of the main basin, while individual such seas can occur in e.g. Gulf of Finland and Gulf of Bothnia.
Especially in Finland and Sweden, boating is a national pastime. There is a boat to every seven or eight people in these countries. This is matched by Norway and New Zealand, but otherwise quite unique (e.g. in the Netherlands the figure is one to forty).
- See also: Nordic history
The Baltic Sea is a young sea. It has changed from fresh water lake to salt water or brackish sea several times during the last 10,000 years. The effects of the Ice Age can be seen at many locations. The post-glacial rebound (see Nordic countries#Understand) is still noticeable in the northern areas, especially in the Kvarken area in the Gulf of Bothnia, a World Heritage Site.
In the Viking Age, Scandinavian seafarers sailed over the Baltic and by the Russian rivers all the way to the Mediterrean and Caspian Sea (in addition to voyages by the Atlantic Ocean).
In the middle ages the German Hanseatic League dominated trade on the Baltic; many of the important ports today were members of the league.
In the late 17th century most of the coast belonged to or was controlled by Sweden.
When steam replaced sail on most trades in the late 19th century, sailships continued to be used in several countries by the Baltic Sea. Germany had cargo carrying schoolships, such as Herzogin Cecilie of Norddeutscher Lloyd Bremen and Passat of the Flying P-Line (now in Travemünde). Gustaf Erikson of Åland was the last major sailing ship shipowner, maintaining a fleet of big sailing ships to the 1940's (Pommern can be seen in Mariehamn). Small wooden sailships for costal trade endured to the 1950s.
The Baltic Sea remains a very important trade route for the countries by the coasts.
English is the language of the sea, at least of this sea. In most countries announcements for seafarers and yachters are made in English in addition to any local languages. Knowing local languages is useful for getting most out of listening to VTS (noting key locations and figuring out how they are pronounced may help a bit). German, Danish and Swedish are Germanic languages like English, so you should be able to understand fragments of the conversation regardless.
On shore, English is well known in Germany, Denmark, Sweden, Finland and by young people also in the other countries. Elder people in Estonia, Latvia, Lithuania and Poland understand Russian, but may not be eager to use the language. There are also big ethnically Russian populations in the three Baltic countries. German used to be a common foreign language in most of the countries with Baltic coastlines but is increasingly losing ground to English. However, especially in Nordic countries you will have a reasonable chance of encountering people who speak it. While Poland, the Baltic countries and to some extent even Russia used to have big German speaking minorities, most of them have either left or been absorbed into the national culture and hence your chances of encountering native German speakers in those countries are slim.
You can come to the Baltic through the Danish Straits, through the Göta Kanal, through the Kiel Canal, by the central European waterway system (connected to the Atlantic and the Mediterranean) or through the Russian waterway system (extending from the White Sea in the north to the Black Sea in the south). For most, chartering a local yacht is the main option. See below.
Pleasure craft arriving to or departing for a Schengen country from another one may do so without calling at a border crossing point and without being subjected to border controls other than random checks. So if you come from a port on the Baltic Sea, except for Russia, you mostly do not have to go through border formalities. See e.g. information on border checks on pleasure craft by the Finnish border guard. Arriving with a dog, arms or other special goods, check the procedures in advance.
Except Russia, all the countries around the Baltic are members of the European Union and the Schengen agreement. You should be allowed to entry the waters of any of these where you want to (with exceptions of military areas and the like) and land without customs or immigration controls, if coming from another of these countries. Check with the individual countries before entry, though: there may be special circumstances. For Russia, and coming from Russia, you have to do all normal formalities. Note that Ireland and the United Kingdom, although in EU, are not part of the Schengen area, while Iceland and Norway, although in Schengen, are not members of EU. Coming from those, check immigration and customs formalities, respectively. Åland has a special tax status within EU, which may have significance if you bring more than tax free amounts of certain goods (checks are unlikely but possible). Coloured (less taxed) diesel is allowed only in the main tanks, and only if bought in the right countries (keep the receipt, even if only traces are left).
In addition to the documents you would need on land borders, you may need documentation about your boat and your qualifications as skipper. You may need the original registration document, an insurance policy and the radio licence of the boat, and a crew list signed by the skipper (in several copies, especially if going to Russia).
For EU boats, proof of paid VAT (or proof of construction before 1987) may be needed. If you import a boat to EU you normally have to pay VAT and tariffs. To avoid this as a tourist there is "temporary import" available for non-EU residents, for at most 18 months, winter breaks not counted if registered by the book. Normally the temporary import is implicit, but the customs can demand your making the paperwork, and in that case you need to have documentation about ownership, registration, residency and time of entering EU. If the boat is staying more than 18 months, it is not leaving with you, an EU resident will use the boat, there will be works other than regular maintenance or there are other special circumstances, check the exact rules, e.g. at Finnish customs about temporary import [dead link].
The winter break regulation should allow you to sail in your yacht, leave it at a yard and return home, return to sail the next season, and so on for several years, given that you handle the paperwork correctly.
You can of course rent a yacht in more or less any coastal town, or you might already have your own yacht in the Baltic. If you have friends who are thinking of importing a yacht, you might be able to come by sailing it to them. For arriving to the town of your choice, see that town.
Generally the qualification you need for a yacht at home should be enough for skippering it in the Baltic. Documentation may be needed. For bare boat chartering also the rules of the flag country apply. Documented competence may of course make bare boat chartering of a big yacht easier whether formally required or not.
The main document about competence as skipper of pleasure craft is the International Certificate for Operators of Pleasure Craft ("ICC"), which is valid for sailing or motor vessels up to a stated size, for either inland or coastal waters. It is officially recognized by Finland, Germany, Lithuania and Poland, but in practice also elsewhere. On inland waters other than in Finland or Sweden you may need the ICC with a mark for inland waters (signifying knowledge of the CEVNI regulations). If you need it for the Baltic Sea you should have the coastal waters mark.
Skippering a normal yacht requires no formal qualification in e.g. Denmark, Finland and Sweden, with Danish flag for yachts under 15m that are not "speedboats", in Finland "sufficient age and skills" [minimum 15 years] up to 24 m. Voluntary half-official exams are quite common. In Estonia you need documented competence according to your flag state rules. Check requirements for other countries.
If the boat has marine VHF radio, a licence for the boat (including a call sign, and MMSI number if applicable) and one for the operator (normally Short Range Certificate, SRC, covering also DSC) is needed.
The Danish sounds
- See also: #Boating in Denmark
There are three sounds between Jutland, the main Danish islands and Sweden, from west to east: The Little Belt, the Great Belt and Øresund, all connecting the North Sea to the Baltic Sea via Skagerak, Kattegat and the Danish and German archipelago. There are huge bridges over all of them. Note currents and keep away from the heavy traffic.
- See also: #Vänern and Vättern
The Göta canal goes through pictoresque landscapes of Sweden, from Gothenburg to Söderköping, via Sweden's biggest lakes Vänern and Vättern, connecting Skagerrak and Kattegat to the central parts of the Baltic Sea, somewhat south of the Stockholm Archipelago. An important industrial transport route throughout the 19th century, it is now used mainly by leisure craft.
The Kiel Canal (known in German as the "Nord-Ostsee-Kanal" or North-Sea–Baltic-Sea-Canal) is one of the busiest waterways in the world, connecting the North Sea to the southern Baltic Sea. You enter via the mouth of Elbe, at Brunsbüttel. The eastern end is in Kiel.
Central European waterways
Rivers and canal systems connect the Baltic Sea with the Atlantic Ocean and the Mediterrean Sea. The CEVNI rules apply, with special regulations in the Kiel Canal and on the biggest rivers.
Vikings used the Russian waterways to get to the Black Sea. Parts of these routes can still be used. Check possible need for special permits, which may be difficult to get.
The White Sea–Baltic Canal connects the Arctic Ocean to the Baltic Sea, via Lake Onega, Lake Ladoga and Saint Petersburg, mostly by rivers and lakes.
Lake Onega is also connected to Volga, so coming from the Black Sea through Russia is still possible.
You can charter a yacht in most of the bigger towns along the coast and in inland archipelagos. You may want to check what documents about your qualifications the company wants, and whether there are restrictions on use of the vessel. If the boat has marine VHF radio, you need a licence.
Crewed chartering is considered expensive. Usually full service charter is offered for a day trip, while bare boat chartering is the norm for longer journeys. You might get a skipper for your one-week charter by asking, but unless you ask for (and pay) full service, you should not assume he will wash your dishes.
Prices for bare boat coastal yacht charter in Finland can be expected to be in the €1000–5000 range for a week, depending on boat, season etcetera. These boats usually have toilet, cooking facilities and 4–8 berths. Typical yachts and prices vary between countries and waterways, as does quality of equipment and service. Take your time to choose. If you have only little time, local offers should suffice.
"Handy size" is good. Not being able to enter that otherwise ideal anchorage because of draft or having to choose another route because of a bridge is a shame. This is more important in some waters than in others.
The Baltic is a busy sea. There are many important cruise ferry and roro routes. Most of Finnish foreign trade is shipped over the Baltic sea, as is a large amount of that of the other countries. Saint Petersburg is one of the most important ports of Russia. Oil transport from Russian ports through the Gulf of Finland to EU is approaching Persian Gulf intensity. All this means that you will want to avoid the main shipping lanes. As a coastal cruising yacht you do not have to use the separation systems and should usually avoid them. There are also a lot of yachts – but plenty of room to be alone.
Although the distance from Kiel to Haparanda is well over 750 nautical miles, one is never more than about 75 miles – a day's sailing – from the nearest coast. There are however areas out of VHF/DSC reach from coast stations, both in the main basin and in Gulf of Bothnia.
Going from Denmark, Germany or Poland to Stockholm, the Archipelago Sea or Helsinki, you probably want to reserve at least a week either way, which leaves a little time to spend also on the shore. In addition you need time to spend at the main destination. The Swedish coast is quite different from the coasts of Poland and the Baltic states (as are the countries), make your choice. If circumnavigating the main basin, going counterclockwise has the advantage of less probability of having to sail upwind off the less sheltered coasts in the east and south.
As explained above, there should be no routine border controls other than in certain circumstances, except for Russia and at initial entry. It seems arrival has still to be reported at least in Poland.
For border controls going to or coming from Russian ports in the Gulf of Finland, see the Gulf of Finland sections.
For Kaliningrad Oblast, check customs facilities near the previous and next port on your route.
With an arm, a dog or other special goods, check the rules for individual countries.
Markings follow the international INT A standard (leave red marks at left when entering a harbour) with minor deviations. The "chart" INT 1 for each country has complete information on the symbols used etc., in the standard format.
You need detailed coastal charts (1:50,000, sometimes more) for the Finnish and Swedish archipelagos. Small scale charts can be handy for planning the voyage, but are useless for navigation in many areas.
Electronic charts can be used, but should normally not be the only ones: pleasure craft generally lack necessary electronic backup systems and have too small displays – essential details may be hidden when zooming out. The latter is especially important in Finnish and Swedish waters, with lots of small rocks.
Notices to Mariners are generally available online, bilingual with English. The notices include notifications of damaged navigational aids, firing exercises, updates to charts etc. For some countries temporary warnings are also listed separately. These are also mostly broadcast as Navtex messages.
Rules for inner waters
For the river and canal systems of Germany, Poland and Russia, acquaint yourself with the CEVNI rules and check local regulations.
Finland and Sweden
Finland and Sweden have large archipelagos, which means rules for inner waters cover extensive coastal areas. Some of these are good to know also for visiting yachts.
Small vessels are not required to have sidelights and can carry its toplight low. Thus a white light often means a quite fast motorboat, with the driver possibly obstructing the light at some courses. Do not rely on him keeping a steady course. Luckily the nights are often light and, regardless, if your lights are in order, he should see you. In Sweden lights have to be used from dusk to dawn instead of from sunset to sunrise, saving you an hour worth of electricity.
In Finland motoring boats with sails set have to use the day shape. In Sweden no day shapes need to be used by small enough vessels.
In Sweden boats without sidelights should keep away from bigger vessels in fairways. In Finland boats of less than 7m should if possible give way for vessels over 12m in fairways. Pleasure craft keep away for professional ones also as a matter of good manners. None of these rules apply when vessels are close enough for COLREG obligations to dictate behaviour, but freighters, ferries and other commercial craft are usually unable to stop or safely give way, as they are confined to the fairway regardless of not having the associated lights or day shape.
Lights and day shapes are not required in safe anchorages away from traffic.
Among the signal flags, you should know A (diver, keep away) and L (stop, shown by police, coast guard etc.).
Mooring, at least in the north, is mostly with the bow towards the shore or quay and a buoy (or the anchor) behind the stern. Local yachts often have arrangements for easy passage to shore from the bow and a rod with a hook and latch for easy fastening to the buoy.
There are many towns and cities worth seeing. See Baltic Sea ferries and Cruising the Baltic Sea for some of them, the country articles for the rest. Besides these there are islands and archipelagos yacht cruisers should know and some villages worth mentioning here. Small towns and villages, even natural harbours, may be nice to visit as variation or even instead of the biggest cities.
Below the coasts and archipelagos are described country by country clockwise from the Danish Straits.
Boating in Denmark
The western and northern shores have tides. Tidal currents are significant in the Danish straits, although also unrelated variations in the sea levels affect the currents. In the Baltic Sea proper, tides are of little importance.
The route to the Baltic Sea goes either through Limfjord in northern Jutland to Kattegat or through Skagerrak around Skagen (the tip of Jutland) to Kattegat. Approaching the southern part of Kattegat you choose which of the straits to use. A variation is to come by the Kiel Canal or Limfjorden and continue via Kattegat to Göta Kanal in Sweden.
Limfjord is 100 nautical miles long, quite different from the Norwegian fjords: shallow, with no mountains. The western part is labyrinthic, partly lakelike, while the eastern part resembles a river.
Also going directly via the Kiel Canal to Baltic Sea proper you will pass by Lolland and Falster.
The main straits are busy with freighter traffic. Remember to avoid the traffic separation scheme clearways and the deep water routes. Use inshore traffic zones and fairways for smaller vessels instead.
The main coast radio, responsible for emergency traffic, is Lyngby Radio, MMSI 002 191 000. If you call 112 and tell you are in a maritime emergency, your call will be transferred to Lyngby Radio.
Denmark has good facilities for yachts, but harbours tend to be crowded. Finding a place for a catamaran can be difficult.
- Funen and Surrounding Islands
- Lolland-Falster (including Møn and small islands)
- Bornholm off Swedish Scania
Boating in Sweden
Sweden has a long coastline, and together with Finland and Norway possibly the highest number of leisure boats per capita. Cruising on small craft is a national pastime, at least when weather allows.
Charts for the major boating destinations can be got as series in a format suitable for small craft, with the most demanding passages (also) in bigger scale. Symbols and practices are not explained in the charts, so INT 1 can be a good investment.
Due to the nature of the waterways in the archipelagos, the "direction" of a fairway is not always obvious; use the chart to check how to interpret lateral marks. Because of this problem cardinal marks are used extensively (with colours given as letters in the chart). Top marks are seldom used. In early spring some marks may be missing or off their position because of ice movements in the winter. Sector lights are common.
Swedish Notices to Mariners are available online.
Most Swedish provinces are coastal, and even those that are landlocked, are dotted by lakes, so an exhaustive list of leisure craft destination would include most of the country. Nevertheless, some classical boating destinations are
- Stockholm archipelago
- Bohuslän archipelago on the west coast, i.e. by Skagerrak
- Gotland off the east coast
- Göta canal
The archipelago that starts at Landsort south of Stockholm continues with only minor gaps all the way to Saint Petersburg in the end of Gulf of Finland, some 400 nautical miles away.
Depending on destination and preferences, a yacht with berths and cooking facilities, a day cruiser, a small motor boat, a rowing boat or a canoe or kayak may be the right vessel. There are lots of guest harbours, but the right to access allows you to use also the endless supply of natural harbours and uninhabited shoreline in the archipelagos, at least if you get out of the busiest areas (but do not disturb nesting birds).
There are a few archipelagos, including those at Bohuslän, Gothenburg and Karlskrona, while most of southern Sweden has a quite smooth shoreline. The entry to Göta canal is by the river Göta älv, with its mouth in Gothenburg.
- Islands by the Swedish coast
- See also: Stockholm Archipelago
There is a large archipelago starting more or less with Öja (Landsort) some 50 nautical miles north of Gotland and extending to Arholma in Norrtälje. The main leisure craft fairway south to north, from Landsort via Kanholmsfjärden, Husaröleden and Blidösund to Arholma, has a length of more than 80 nautical miles. The archipelago has some 24,000 islands and islets on an area of 1,700 km².
The Baltic Sea end of the Göta canal is nearby to the south (in Söderköping). The southern entry to Lake Mälaren is through Södertälje canal, with Södertälje in a long narrow bay of the southern Stockholm archipelago. The other entry to Mälaren is through Stockholm itself.
The Åland islands and the Archipelago Sea in Finland are close by: the passage over the Sea of Åland from the north end of the Stockholm archipelago is short enough for nearly any vessel on the right day. Thus these three archipelagos could be seen as one destination, in fact continuing along the Gulf of Finland all the way to Saint Petersburg.
The archipelagos share many characteristics. There are myriads of tiny islets, interspersed with bigger islands with villages or even towns. The nature is varied, with harsh rocky islands in the outer archipelago and lush vegetation in the sheltered parts of the bigger ones. There are lots of summer cottages, yachts, tour boats and marinas. Stockholm Archipelago is by far the busiest, but even here there are many areas with little traffic.
Navigation is demanding, because of the relatively shallow waters and the many rocks and islets, but fairways are well marked and charts reliable at least in the busier areas. Once one is acquainted with the challenge, the archipelago offers nice sailing with constantly changing views. Many people cruise here for weeks every summer, still finding new places to visit.
- Utö – an outer-archipelago idyllic island with a closed-down silver mine, and remnants from the mining industry. Do not confuse with Utö in Finland, across the sea.
- Sandhamn – the largest island in the outer archipelago, known for its summer nightlife.
- Väddö kanal – a long narrow passage between Väddö and the mainland, with canal passages, small lakes and wetlands, and corresponding countryside landscapes and wildlife
If crossing the sea to Åland, note change of timezone and currency. Though the passage is short, with southerly or northerly winds the seas can be rough indeed. Depending on your vessel, you might want to have some extra days to wait for (the very common) westerly winds.
Lake Mälaren, accessible via Stockholm and the Södertälje canal has a complex archipelago with thousands of islands and islets, somewhat resembling the Finnish lake systems. It is third in area of the Swedish lakes. Ekerö is a municipality of islands, containing the Drottningholm Palace, as well as Viking-Age city Birka.
Vänern and Vättern
Göta Kanal gives access to the two biggest lakes of Sweden, Vänern and Vättern.
Swedish coast of Gulf of Bothnia
Höga kusten ("the high coast") in the north part of the Bothnian Sea is a world heritage site together with the Finnish Kvarken archipelago. It is a popular destination for Swedish (and Ostrobothnian) yachters, which means there are facilities along all the coast. On the Swedish side the sea is often deep even close to the shore.
As the Gulf of Bothnia is sheltered by the Scandinavian mountains, winds are mostly quite light, especially in the (light) night.
If circumnavigating the Bothnian Sea, going counterclockwise may be the better option, because of coastal currents of 0,2–0,3 knots, giving a bonus of 50 nautical miles compared to going clockwise.
Boating in Finland
As Finland is at high latitude, the sailing season is quite short. The peak season is from Midsummer in late June to when schools start in mid August. This is the time when most Finns have their summer holidays. It is often nice May to September in the south, but in spring and autumn you should be sure to dress adequately and check what marinas are open. Also fog is more common than in the summer.
Late autumn and early spring can be nice also – if you like being alone and know what you are doing. There are people heading out as soon as the ice leaves (usually in April in the south), but be very careful if there may still be some ice floating around or marks missing or moved by the ice. Likewise some are out until December, but then having to cope with a snowstorm is quite possible. Storms are much more common in autumn than in spring and summer. In spring, temperatures at sea are lower than inland, as the water is still cold (and the other way round in autumn).
The main lanes for commercial shipping are of course well marked and sometimes the only option, but the busiest ones are best avoided when there are alternatives. Lesser fairways crisscross through the archipelagos, used by pleasure craft as well as ferries and small freighters. There is a system of well marked main boating fairways, and also separate half-official boating routes (the depths of the latter are not guaranteed but trusted by most boaters). Blue and white cardinal marks are used for some informal routes. Outside fairways and boating routes you have to use your judgement. The depth figures usually give a good general picture, but not all areas have been covered with modern sounding techniques (for the Archipelago Sea just some 10 %) – where depth figures are deduced from lead line sounding (yes! there may still be some such areas) or traditional echo sounding one should navigate cautiously, as there may well be rocks or reefs between sounding points or sounding lines, at least in shallow water. On the other hand, on routes that have been extensively used, official fairways or not, most rocks should have been found.
You need detailed coastal charts (1:50,000) for the archipelagos along most of the coast. Small scale charts can be handy for planning the voyage, but are useless for navigation in many areas. The detailed charts come in two versions: single standard charts (à €20) or as series of a format more handy for small craft (à €47). Most of the relevant inland waterways are covered by chart series like the coastal areas (mostly 1:40,000).
Finnish charts now use WGS84 and standard INT symbols with minor deviations (the charts for some lakes may still use the national coordinate system and different symbols and colours). The "chart" INT 1 (€20) has complete information on the symbols used etc., in the standard format. It is used by few locals; the chart series include a brief symbol explanation and other useful information (also in English).
Because the fairways crisscross around the archipelagos, instead of leading from the sea to a port, their nominal directions are not always obvious (check the chart). Therefore cardinal marks are used extensively, also large fixed edge marks up to 50m off the fairway (likewise: check the chart). Topmarks are seldom used, despite the symbols used in Finnish charts (colours are not given in the chart itself, you should know them). The edge marks have large radar reflectors, which can be mistaken for topmarks.
Electronic charts can be used, but should normally not be the only ones: pleasure craft generally lack necessary electronic backup systems and have too small displays – essential details may be hidden when zooming out. The latter is especially important in Finnish and Swedish waters, with lots of small rocks.
See Information on Finnish charts and publication by the Finnish transport agency. Authorized reseller is Karttakeskus. The charts and books are available also at e.g. yachting shops and bigger book stores.
You might also want a book on guest harbours e.g. the semi-official Käyntisatamat-Besökshamnar (one volume on the coast, €23, another on the lakes) or The Great Harbour Book by an Archipelago Sea scout troop. Käyntisatamat-Besökshamnar is updated yearly and covers all official guest harbours. The Great Harbour Book has four volumes, with about 140 harbours each: Part I–III (à €65) in Finnish and Swedish, covering the Archipelago Sea, Åland and the Gulf of Finland, respectively, including also some natural harbours, Gulf of Bothnia (no number; €65) in Finnish and English, and Part IV (€73) in English and German, with an assortment of harbours covering also the Stockholm region and the Estonian coast. Charts and symbols should be comprehensible regardless of language.
Finnish NtM index is in Finnish, while the notices themselves are trilingual.
Listening to VTS can give early warnings on ships approaching narrow passages. There is an experiment (2015–2017) where participating vessels primarily use English, so less Finnish and Swedish than normally will probably be heard.
There is an abundance of marinas and lesser guest harbours. Among the locals many mainly use natural harbours when not in need of electricity, sauna, washing machines and the like. Mooring in natural harbours is generally allowed, but anchoring close to cottages (which sometimes are hard to see from a distance) is frown upon and using private jetties without permission is forbidden. When coming from abroad, the diversity of marinas and nearby villages and nature may be enough for quite some time.
Official guest harbours are marked on the charts. Some anchorages and jetties (such as those of some authorities) can be used for temporary refuge. Quays for sparse-timetable ferries can be used for loading and unloading, but not in ways disturbing the traffic.
Especially in the Archipelago Sea, where tourism is an important income, most inhabited islands have a jetty for visiting yachts and provide some service, such as selling fish or handicraft or providing sauna. Prices for staying overnight (with a normal yacht) at a guest harbour varies from €5 on some of these islands to perhaps €15–35 for marinas with full service.
Natural harbours can be found in some harbour books, by discussions in marinas or by studying the chart combined with trial and error. Be sure to study the anchorage before trusting it to be safe, especially regarding underwater rocks and forecasted winds. A wedge for fastening a line to a crack in the rock can come handy, but mostly you can attach lines to trees and rocks. Locals seldom use dinghies, but jump from the bow to the shore (which can be quite steep, and slippery if wet).
Major marinas can be trusted to have fresh (potable) water, electricity, showers and sauna, usually also wastewater collectors (pumping toilet water to the sea is forbidden). Marine fuel stations have become rarer, but hardly to the point of it being a problem.
For emergencies at sea in Finland (or anything that might develop into one) contact the maritime rescue centre (MRCC Turku for most of the coast and sea, MRSC Helsinki for Gulf of Finland), VHF 70/16 or phone +358 294-1000 (shared number). The general emergency number 112 can also be used, they will send the coast guard (responsible for distress at sea) or the lifeboat institution to help you if needed, but often have a pretty obscure picture of the conditions in the archipelago, so be prepared for some frustration. For lakes, use 112 except on the main fairways of Saimaa, where Saimaa VTS may be better, depending on the kind of emergency. Also the lifeboat institution listens to VHF 16 on most big lakes in season.
Mobile phones mostly work in the archipelagos, but expect lack of coverage here and there. VHF can be used to contact authorities, major marinas and many yachts. Primary channels between leisure craft are L1–L3 (155.500, 155.525 and 155.650 MHz), 77 and 72; channel 16 can be used for calling up any vessel.
Finnish coast of Bothnian Bay
Bothnian Bay (Perämeri, Bottenviken) up north is where Sweden and Finland meet. Spring comes late up here, with restrictions on freighter traffic still in effect (ice class IA required) in middle May a typical year.
- Inland entity: Northern Ostrobothnia
- Harbor map @ guestharbours.fi - Set G, Bothnian Bay 46 harbors
- The Finnish chart series G covers the Finnish coast of the Bothnian Bay.
- Tornio (Torneå) at the border to Sweden, the oldest town in Finnish Lapland, with charter from 1621.
- Oulu (Uleåborg), a university town at the mouth of Oulujoki, the biggest city in northern Finland and the fourth biggest metropolitan area in the country by population. Guest harbour in the heart of the city. Oulu is the city where Jarkko Oikarinen wrote the first irc server and client in August 1988.
- Raahe (Brahestad) 64°41 15` and 24°27 60` 
The Kvarken Archipelago (Merenkurkku, Kvarken) is an UNESCO world heritage site and naturally very beautiful. Postglacial rebound (nearly a centimetre a year) causes the shallow seabed to rise, uncovering pristine new land every year. The land forms (seen as islands, capes, rock deposits and reefs) were created by the ice age glacier.
Because of the northern latitude, there are no dark nights in most of the summer: dusk becomes dawn and the sun rises again. The skies are also often clear; the area is one with most sun hours in Finland. The water is clean, and as it is shallow it becomes quite warm (18–21°C south of Vaasa).
Navigating unmarked waters is difficult, as there are lots of rocks on the shallow seabed. The ice can move rocks in shallow water, so outside fairways (where new rocks will be dealt with in the spring) charts cannot be totally accurate. There are well marked fairways, though, and boating channels have been made deeper the last years to accommodate growing depths of modern yachts. Some destinations are still unreachable with 2m keels. Be wary about variations in sea level.
Circumnavigating the Bothnian Sea counterclockwise, options for crossing to Sweden include the route via Norrskär to Järnäs or Norrbyskär (smaller vessels; lighthouses in sight all way and mobile phones mostly working); the northern route around Replot or from Jakobstad towards Byviken in Holmö off Umeå; and going more or less directly to Höga kusten near Örnsköldsvik, from Fäliskär to Skeppsmalen, Trysunda or Ulvön.
- Inland entity: Ostrobothnia
- Harbour map @ guestharbours.fi - Set F, Kvarken lists 51 harbors
- The Finnish chart series F covers the Finnish part of the Kvarken Archipelago.
- Kokkola (Karleby), which had one of the largest merchant fleets in Finland during the 18th century and was a major producer of tar and ships. Large well preserved wooden old town.
- Jakobstad (Pietarsaari), home to the Nautor Swan, nearby Larsmo is home to to Baltic Yachts.
- Vaasa (Vasa), the main town of Ostrobothnia. Good service for yachts. The main Kvarken archipelago is in the surroundings, out to Fäliskär, Norrskär and Valsörarna.
Finnish coast of Bothnian Sea
- Bothnian Sea (Selkämeri, Bottenhavet)
- Inland entity Satakunta
- Harbour map @ guestharbours.fi - Set E, Bothnian lists 22 guest harbors.
- The Finnish chart series E covers the Finnish coast of the Bothnian Sea.
- Vaasa (Vasa)
- Pori (Björneborg) 61°37,0’N, 21°26,4’E hosts the Pori Jazz festival on 9-17th July
- Rauma (Raumo) 61˚8,85'N 21˚28,145'E 
Åland is an autonomic demilitarized island group with tight connections to both Finland and Sweden, on the route to Stockholm if coming from east.
- Harbour map @ guestharbours.fi - Set C, Åland islands lists 30 harbors. The Great Harbour Book has a volume on Åland with 140 harbours (including natural harbours).
- The Finnish chart series C covers the Åland islands.
- There is a border crossing point in Mariehamn, which can be used if e.g. coming directly from Kaliningrad.
Coming from Sweden, across the Sea of Åland, the main points of entry are Eckerö and the capital Mariehamn (with two marinas, choose in time). Most people cruise the southern and eastern archipelago, north of the main islands you will be quite alone, although there are villages also here. Thanks to the autonomy and small population, there are much less summer cottages in Åland than in Sweden or Finland proper.
Archipelago Sea (Skärgårdshavet, Saaristomeri) is a scenic and serene classic. It is explorable also with bicycle and car because of the network of small ferries connecting the bigger islands, but with boat all of it is in reach.
- Harbour map @ guestharbours.fi - Set D, Archipelago of Turku lists 91 harbors. The Great Harbour Book has a volume on the Archipelago Sea with 140 harbours (including natural harbours). See also visitsaaristo.net.
- Inland entity: Finland Proper.
- The Finnish chart series D covers most of the Archipelago Sea.
- Partiosissit has a book on 2,000 nautical miles of unofficial routes, in addition to the 900 nautical miles of official fairways and boating routes.
- Archipelago VTS uses VHF channel 71.
The archipelago is a wonderful place for small craft cruising. Mostly the waters are open enough for relaxed sailing, but the landscape is constantly changing. There are myriads of islands to land on when you feel like, and guest harbours not too far away.
Although fairways are well marked and there is a lot of navigable water outside them, foreigners used to more open waters will probably have quite a challenge in adjusting their navigation techniques, before being able to fully enjoy the experience. Going down under to check the chart is not the way to navigate here.
The permanently inhabited islands, at least the remote ones, tend to have some kind of guest harbour and service for tourists. For electricity, waste bins and showers you should head for the bigger ones, but sauna, freshly smoked fish, handicraft or a nature trail may be available anywhere.
Most waters are sheltered, so with some care and checking weather forecasts you might get along with any vessel. For longer journeys a yacht with cooking and sleeping facilities is nice – and the most common choice – but if you did not come with one, also a smaller vessel, even a kayak, can be a good choice. Regardless of craft there are always new places to explore.
- Main ports in the Archipelago Sea
From north to south towards east
- Uusikaupunki, the main town of the Vakka-Suomi region, an important ship building and shipping centre in the 19th century. Empire style wooden old town.
- Naantali is a solid sailing destination and known as one of the most beautiful and bustling guest marinas in Finland. The President of the Republic of Finland has his summerplace Kesäranta within binocular-sight and the Muumimaa Moomin Troll Theme Park is a hit with the kids. Naantali features a luxurious spa hotel and a wooden old town with shops, cafés, exhibitions and restaurants. Not accessible with height over 16.5 m. With mast over 11 m, check which route to use.
- Turku, the former capital, has a guest marina up the Aurajoki river.
- Nagu, with the biggest marina in the region, between Naantali and Turku to the north and the outer archipelago to the south.
- Pargas is immediately south of Turku on the eastern side of Airisto; the town itself is on the route from Helsinki to Airisto, but accessible only by long sounds.
- Kasnäs and Dalsbruk in Kimitoön lie at the main fairway eastwards to Hanko and Helsinki.
You should definitively visit also minor islands. Utö, (Korpo-)Jurmo and (Nagu-)Nötö are classics not to miss if nearby, while countless others are nice as well. See Archipelago Sea.
Gulf of Finland, Finnish coast
The Gulf of Finland stretches from Hanko to Saint Petersburg, a distance of some 220 nautical miles, while the distance across it easily can be covered in a day. The ferry traffic between the capitals of Finland and Estonia, Helsinki and Tallinn, is frequent, as is freighter traffic through the gulf.
There is an archipelago along much of the northern coast, giving shelter from the sea unless you choose an outer route. The outer archipelago is hard to navigate, so seeking shelter only when the sea gets rough is not necessarily easy. The archipelago is similar to the Archipelago Sea, but much more narrow; you will see the horizon every now and then even keeping to the inner fairways.
On sunny summer's days there is often sea breeze in the afternoon, and corresponding light land breeze in the night.
Coming from Saint Petersburg or Vyborg, the nearest border control points in Finland are Santio for the inner fairway and Haapasaari for the off shore route. There are also border control stations in Suomenlinna off Helsinki, in Hanko and in Mariehamn. You have to visit a border control point also on the way to Russia, even if on your way to Saimaa.
- Santio border guard station (at the inner route from Vyborg Bay), ☎ . 08:00–22:00. With marine VHF, use channel 68 or 16.
- 1 Haapasaari (Aspö) (outside Kotka), ☎ . 08:00–22:00. With marine VHF, use channel 68 or 16. The island is a local cruising destination, with a guest harbour. You can seize the chance to explore the island, buy fuel etc. after clearance.
The Gulf of Finland is divided in the part west respectively east of Helsinki and Tallinn. The Hanko peninsula is regarded the border between the gulf and the Archipelago Sea.
- Inland entity: West Uusimaa
- Harbour map @ guestharbours.fi - Set B, Parainen (Pargas) - Helsinki lists 70 guest marinas from Pargas to Helsinki
- Western Gulf of Finland is covered by Finnish chart series B, which overlaps with the Archipelago Sea series.
The Finnish coast of Eastern Gulf of Finland stretches from Helsinki to the Russian border.
- Inland: East Uusimaa and Kymenlaakso.
- Harbour map @ guestharbours.fi - Set A Virojoki - Helsinki lists 58 guest marinas east of Helsinki
- Eastern Gulf of Finland is covered by Finnish chart series A, which extend to Vyborg in Russia.
- Sipoo archipelago is nice
- Porvoo(.fi) [dead link] is a renowned destination with a well preserved old town by the Porvoo river's mouth.
- Loviisa(.fi) is a mellow laid back town with an interesting island fort south of it.
- Kotka is an old port and marina city. The apex of Kotka summer is the Kotkan Meripäivät(.com) in the end of July
- Hamina(.fi) has the Hamina Tattoo in the start of August 
- Virolahti is where Finland ends.
- Pyhtää, Kotka, Hamina, Virolahti and Miehikkälä market their travel offerings together.
Via Saimaa Canal (Saimaan kanava, Saima kanal; 43 km) you can access the scenic Saimaa lake system. This requires briefly passing through Russia since the Gulf of Finland end of the locks is in Russia. See Saimaa Canal instructions.
No Russian visa is required to pass if you do not plan on stopping over at Vyborg, but there are requirements on the craft, master and documents. You have to clear with Finnish customs before leaving Finland, and customs routes have to be used. A marine VHF radio is needed if you do not want a pilot between the Vihrevoi island and the Brusnitchnoe lock. (USD30 in 2010). The Finnish chart series A and S cover the coastal route from Helsinki to Vyborg and onwards to and through the canal, respectively.
While in Russian waters and in the canal section on Russian territory deviating from the fairway is not allowed and landing is strictly forbidden. Staying overnight (in the boat) is allowed only at specific places. If visiting Russian ports, see Boating in Russia below.
The Finnish lakes
Most of the waterways described here are at least partly labyrinthic archipelagos, with islands, capes, bays and narrows, in addition to the more or less open bodies of water. There are always things to explore off your channel, if you have the time. There are also other kinds of lakes, but those are relevant mostly if you rent a cottage at their shore. Lake shores and islands are popular for summer cottages, private or rentable, but there is so much shore that much of it is left alone.
Many lakes are large, but if you want to explore the waterways of e.g. Saimaa, Päijänne, Näsijärvi or Längelmävesi from end to end you will also need to go through locks. Get a guidebook on rules for the inner waterways. Many locks are self-service, but they are quite easy to use.
Depending on intended routes, smaller craft than by the coast can be handy. On many lakes day sailors are common. Staying overnight in a tent or a hotel instead of in the boat is often a serious option – as is renting a cottage and using a small rowing or motor boat, sailing dinghy or canoe to explore the surroundings. That said, many of the lakes are large enough for comfortable sailing with proper yachts. Bridges and power lines restrict mast hight. The lower the mast the better, but hight over 12 m will seriously restrict your options. On the main shipping routes of Saimaa the limit is much higher (24m?).
Of the lake systems, only Saimaa is directly accessible by yacht. For the other lakes you mostly have to charter a yacht or smaller boat locally.
Saimaa lake system
Lake Saimaa is very large: 1,147 to 4,377 km² depending on what is counted (443 to 1690 square miles), fifth largest in Europe, with some 14,000 islands. It is situated in the administrative districts South Savonia and South Karelia. The connected navigable waterways, also with big lakes, reach all the way to Mikkeli (with high mast to Ristiina 15 km earlier), Iisalmi (North Savonia; 12 m hight restriction near Kuopio) and Nurmes (North Karelia; 10.5 or 12 m hight restriction in Pielisjoki, Joensuu, some 250km from Lappeenranta).
Chart series L, M, V and R cover most of the connected waters.
The nature of Saimaa is astonishingly beautiful.
Cities of Saimaa include
- 1 Ilosaarirock. The Ilosaarirock Festival is an annual rock festival held in Joensuu on the second weekend of July. Founded in 1971, Ilosaarirock is the second oldest rock festival in Finland still active, and one of the oldest in Europe. Ilosaarirock gathers about 21,000 daily visitors and has been sold out in advance every year since 1998.
- Lappeenranta South Karelia, where you enter if coming by the Saimaa canal, is home to Finnish fast foods atomi, vety and vetyatomi which are filled pies.
- Imatra is also part of South Karelia
- Savonlinna(.fi) in South Savonia hosts the annual Savonlinna Opera festival from July 8 to August 6 (.fi)
- Mikkeli (.fi) is an old city of historical significance located also in South Savonia
- Varkaus(.fi) in Savonia
- Near Jyväskylä.
- East and south of Tampere.
- North of Tampere.
- By Inari.
Boating in Russia
As Russia in not a Schengen country, you need to go through border formalities and probably get a visa. Check procedures in advance.
- Island of Gogland (Suursaari of Finland before the war) is in the middle of the eastern Gulf of Finland and is classified as "border area" and therefore there is lot of red tape for foreigners to get here. The island is known for it's beauty and used to be a vivid destination for domestic holidaymakers before the WWII.
- Kronstadt is a city and military seaport on Kotlin Island
- Saint Petersburg, the Venice of the North
- Ladoga, the largest lake in Europe (17,700 km²), is just some 40 nautical miles upstream the peacefully flowing Neva river from it's delta known as modern day Saint Petersburg.
Boating in Estonia
Estonia has some great boating destinations especially The West Estonian archipelago with widely different looking sights than the archipelagos of Finland and Sweden.
The yachting tradition was largely interrupted by the Soviet rule. Facilities have been built since the independence and are good in many locations, but guest harbours are fewer than along the Finnish coast and standards vary.
The coast is not like the archipelagos in Finland, but largely sandy beaches. The waters are shallow and rocky; keeping to the fairways is usually necessary when sailing near the coast.
Estonian north coast
- The River Narva marks the Estonian-Russian border in East Estonia
- Lahemaa National Park by the coast in North Estonia
- Tallinn, the capital city of Estonia, has many guest marinas. Tallinn was a strong trading port in the Hanseatic League in the medieval times. This was partially due to the extreme ease of sailing safely into and from the port of Tallinn on most winds as practically the whole Bay of Tallinn is deep and practically free of natural hazards on the approach, save a few exceptions easily avoided with modern charts. Tallinn is considerably more expensive than the rest of the country.
- In the Old Town Marina at N 59°26,32' E 24°45,32' the medieval Old Town is only 15 minute walk away. The entrance to the Old Town Marina is actually through the same entrance in the wavebreaker as the huge commercial ferries enter the busy passanger ports. There is a fish restaurant in the guest marina area and various competitively priced and well stocked stores, hotels and restraurants in the immediate vincinity.
- Pirita on the western bank of River Pirita features 2 guest marinas. The Pirita Sailing and Recreation Centre was the home harbour of the 1980 Moscow Olympic Games sailing events and is bustling with life in the summertime. Pirita is a larger complex with a very popular sandy beach, a hotel displaying the brash architectural aesthetics of the soviet of that era and some restaurants, pine forest walks and pop-up food wending in summertime. There is a very impressive ruin and a lovely botanical gardens just nearby.
- Laulasmaa is a small coastal village in North Estonia with nearby Lohusalu Marina N 59°23,2' E 24°12,6
- Paldiski used to be a highly closed military base in the soviet times.
- Nõva is a small coastal village in North Estonia
- Osmussaare is the last island before reaching the Western Estonian archipelago. It is mostly in natural state.
Estonian archipelago and western coast
Hiiumaa and Saaremaa are the biggest islands of the West Estonian islands and hit destinations also for domestic holiday makers. Both offer sights of scenic beauty with vast unpassable juniper forests, meadows and leaf forests and important age old lighthouses. The history of these islands is interesting and the wood building style is a thing to see. Both islands are connected to the mainland with around the year service by small ferries and have various many good guest marinas. The water is shallow, so you mainly have to keep to the fairways, and navigate accurately at entry from the sea.
- Haapsalu is an old spa city famous for it's mud bath treatments and castle ruins. Grand Holm MarinaN58°57.50' E23°31.61'
- Hiiumaa is renowed for its natural beauty and also important lighthouses (the Kõpu lighthouse is from 1531, third in age of active lighthouses worldwide). Vormsi is a smaller island between Hiiumaa and mainland.
- Saaremaa has populated history of 8,000 years and the island's main city is Kuressaare located on the south shore of the island. In the west is the scenic Vilsandi National Park with a small island of the same name..
- Muhu is an island between Saaremaa and the main land. Lounaranna Sadam guest harbour N58°32.458' E23°19.163 on the southern shore of Muhu.
- The Muhu straight between Hiiumaa and Vormsi and between Muhu and the continental Estonia is shallow with water depth rarely exceeding 10m anywhere but is a safe fairway to the Bay of Riga even for deeper swimming vessels. Naturally with calm seas the swimming water gets very warm in the waters of Muhu.
- Matsalu National Park is situated 30 miles south of Haapsalu on the mainland coast.
- Pärnu is renowed sunbathing city by the north of Bay of Riga, at the mouth of Pärnu river and on the Via Baltica.
- Kihnu is the largest island in the Gulf of Riga
- Kabli is a small coastal town 10km north of the border to Latvia
- Ruhnu is a small island in the middle of the Gulf of Riga
To the west is the Irbe Strait towards south-western Latvia and onwards and to the southern end of the Bay of Riga is the Latvian capital Riga
Boating in Latvia
The main rivers flowing into the gulf are Daugava, Lielupe, Gauja, and Salaca.
Boating in Lithuania
Main cities and towns on the coast are
The river Neman has been connected to Don via the Dnieper–Bug Canal (allowing shipping to the Black Sea), but some of the canal is in disrepair. A river cruise to Belarus may still be possible.
Boating in Kaliningrad Oblast
As Russia is not part of the Schengen area, you have to go through border formalities and probably need a visa. Check requirements beforehand.
Boating in Poland
Biggest polish city on the Baltic Sea coast is Gdansk, a city famous for its dockyards instrumental in formation of the Solidarność labor solidarity movement in 1980 which became a reactive catalyst towards the collapse of the soviet system. The Gulf of Gdansk is also one of the main yachting areas, the other being around Szczecin in the estuary of the river Oder (Odra).
Call the authorities when approaching a port. Although Poland is part of Schengen, some formalities may be needed. Similarly when leaving a port.
Weather reports on MF and VHF in English and Polish. Also Swedish Navtex weather reports can be used.
Boating in Germany
The Baltic Sea Coast of Germany is a vacation region located in the northern federal states of Schleswig-Holstein and Mecklenburg-Western Pomerania. The eastern part of it is known as the German Riviera. Besides the obvious draw of a beach destination, many of the old towns in this area bear witness to the former wealth of Hanseatic cities and are well worth a visit.
- German NtM (Nachrichten für Seefahrer, bilingual in German and English) are available through BSH
Water at sea is cold. Life jackets are necessary even when the shore is near. Keep your clothes on to stay warm longer.
Although there are no hurricanes, you should respect the sea. Waves are generally steeper than in the ocean. Thunderstorms will quickly create gale force winds. There are weather forecasts available on NavTex, marin VHF, FM radio and Internet, and at bigger marinas. Use forecasts for mariners, as weather on land can be quite different.
With speedboats, use the dead man's switch. To get back into a boat without stairs or swimming platform, you can use the outboard motor (provided it is off). Small boats are best entered at the stern, as they will not capsize easily that way. Keeping to the boat in emergencies is nearly always the best option – it often stays afloat even if holed and both helps you and is more easy to find, while it is easy to underestimate the difficulties in reaching the shore – and getting up on a slippery rocky shore even when there.
During the long winter nights the Northerners developed a taste for strong drinks. So when civilisation made its mark during the 19th century, there were National rules introduced in order the rule in these bad habits. Even to day you will find sales heavily regulated in a otherwise modern country as Sweden. You can only buy liqueur, wine and strong beer from the stores allowed to do so. And do not expect to find one in every little harbor town. So load up while you can. Preferably in Germany where prices for these necessities of coastal navigation are priced markedly below what you will find further North.
Disposal of garbage in the Baltic Sea is forbidden, with varying degrees of control. Septic tanks emptying is provided in many guest harbours, at least in Finland and Sweden. Denmark is also slowly catching up (one must be 12 sea miles or more from shore in order to discharge legally – avoiding local problems, but still burdening the sea)
There are GMDSS A2 areas in the Baltic Sea, but you can easily choose your route such that you mostly or always are in the GMDSS A1 areas, with coast station VHF/DSC coverage. In some countries, e.g. Germany and Sweden, there are coast radio stations that connect calls to and from the public telephone network.
In the Nordic countries and Estonia the VHF channels L1 and L2 (155.500 and 155.525 MHz) are available for communication between leisure craft. In Finland (and Norway, Iceland) also L3 (155.650 MHz) is available. L2 can be tried also as calling frequency.
Where leisure craft are allowed to use channel 16 and the normal ship-to-ship frequencies, keep use of these channels strict. If available and legal in the area, use L1–L3.
Mobile phones work well in most guest harbours and often near the coast, but ordinary base stations have a maximal reach of 35 kilometres (less than 20 nautical miles), even when in line of sight, so at sea they are of limited use. The archipelagos are mostly covered, but expect some areas without coverage.