Aggregators
Aggregators are search engines or booking agencies that combine information about many hotels, transportation providers or the like.
Understand
Most of the time you can book hotels, flights, buses, trains, cruises and car rentals directly through the aggregator (who may receive a commission for your booking) but there are also those that only list prices and direct you to other pages for booking. While aggregators are not strictly essential and goods or services booked through them can be more expensive than those booked directly, they can be a godsend in weeding through countless offers for example in air travel.
For hotels, cruises, etc., only the major players may be part of the comparison. Thus, especially for off the beaten track destinations, you might want to use other means to find local businesses.
Aggregators are notorious for displaying different prices to different customers based on browsing history, past purchases, and other inscrutable factors. Reportedly, it helps if you clear your cookies or switch your browser to "private browsing" mode before opening one of these websites.
Aggregators generally aren't linked on other Wikivoyage pages, which aim to list transport operators or hotels directly.
Cashback
Various goods and services when booked online can be gotten with a certain "cashback": a website gets a cut for every sale they enable and they hand on a part of that cut to its users. Cookies from an aggregator search can cause the cashback to be rejected, so surf with caution.
Missed connections
If all legs of the trip are with the same company or alliance, they usually take responsibility to rebook you onto the next flight/train/bus in case of a delay that lets you miss the originally planned connection. When you book the legs from different companies, you are often on your own.
Some aggregators explicitly guarantee their connections (even if booked on different companies) when booked through them. This may be the only way to ensure you'll be rebooked, avoiding the hassle and costs of having to book hotels and new flights yourself, when stranded at the airport. By no means all aggregators provide that guarantee, and even when they do there may be caveats like "hand luggage only". Read the fine print. If no such guarantee is given, the territory gets very murky.
Air travel aggregators
Nowadays air travel is only rarely booked directly through the airline without first searching and comparing prices. Sometimes the same flight can have vastly differing prices at various agregators and it pays to compare search results and to also look at the website of the airline itself before booking.
Rail air alliances, especially rail&fly are frequently difficult or impossible to book through aggregators and the vast majority of them won't know IATA codes for railway stations or rail&fly as a whole (QYG). You might have better luck directly with the airline, but sometimes the easiest way to book stuff like this is to actually go talk to an actual human. Given that rail&fly must be booked with your ticket for most flights (some airlines allow it to be added later on, but not even all airline staff know that) and offers both a better price and more flexibility than booking a train trip separately, this is no small thing, especially when you know the price difference to be considerable. Another frequent annoyance with air travel aggregators is that they often want to upsell or offer you hotels, rental cars and the like that you might not need or want all things considered or that can be gotten cheaper through other sources. Aggregators are also known to use cookies to see which flight routes you want to buy, charging you more for a flight you desperately want to take: clear cookies, use private or incognito browsing or search from a different browser or computer to diminish this issue.
If you are flexible with your dates, some aggregators allow searches for +/- three days and others display prices for different departure dates, but you'd have to run the search again to see how accurate those are. Some airlines, most notoriously Ryanair and Southwest, may not show up in aggregator searches, so it might pay to compare with those as well.
- Kayak — a popular aggregator, good at finding cheap flights, with lots of options to modify your search.
- Momondo — reliably finds the cheapest (or close to the cheapest) option available. Good user interface. Allows you to search by frequent flier alliance if you're looking to accumulate miles.
- Google Flights — fast but doesn't always find the cheapest options. Has features that show you the best dates to fly if your dates are flexible and the cost of different destinations if you haven't yet decided where to go.
- Skyscanner — includes some airlines that don't usually appear in aggregators, and allows you to set up to 30 "watchdogs" to search for unusually cheap fares (often errors by airlines, which can allow you to travel very cheaply if you act fast). Also lets you search without specifying a destination so you can see what destinations are cheapest for the chosen dates. "Whole month" feature does not usually work on secondary destinations.
- Flightnetwork — pairs several low cost airlines that normally other aggregators do not pair making it a great option for international routes.
- Kiwi.com — allows search from multiple airports to multiple airports, on flexible dates. Sells tickets at higher prices, but it is possible to just find the flight and buy it elsewhere
- Tripchemy — fast and cheap multi-city round trip search engine for destinations in or around Europe. You buy the tickets yourself using Google Flights. Great if you want to visit multiple destinations on a budget.
- CapeTowncheapflights — global flight comparison and travel website, which uses 728 airlines and some travel agencies to list prices and direct you to appropriate booking pages.
To find a low-cost/no-frills flight it can be good to check one of the comparison tools, such as, e.g., flylowcostairlines.org.
Sites such as Expedia and Travelocity can help you explore your options, but these may not show budget airline flights, and they are rather North America-centric, often showing ridiculously inflated (full-fare) prices for travel outside North America.
Train aggregators
In general booking through the railway directly will get you the best fares, but in some cases there are different railways to compare and tickets across several countries can be challenging to book online.
Bus aggregators
Overall, the bus market is still largely separate for separate countries, in part due to the large travel times involved in crossing any significant distance.
The aggregators usually cover only part of the market and may have deficient name engines, so "no connection" may mean that the company providing the service has no agreement with the aggregator, or that the server did not understand that a bus with a stop on the thoroughfare instead of at the bus station is good enough for you.
International
- Andestransit.com covers all countries in South America. Worth a look along with other sites, but leaves something to be desired in terms of accuracy and completeness.
- Busbud covers most operators in the US, and operators in 62 other countries
- Busradar now covers many parts of Europe, with varying level of completeness. See Germany below.
- busticket4.me covers 27 European countries
- Check My Bus searches for buses in 47 countries
- RedBus covers Colombia, Peru, India, Indonesia, Malaysia and Singapore in separate portals.
- Tickets Bolivia for buses and trains
- Horarios de Buses - schedules only, but there are no prebooking discounts for local buses anyway.
- Matkahuolto sells tickets and maintains a route planner for nearly all non-local bus services in Finland, since way before the web. It also maintains the network of bus stations and agents substituting bus stations.
- Perille.fi combines bus and train connections, has also domestic flights
- Matkakeisari.fi - bus and train connections
- Pikavuorot.fi - bus and train connections
- See also: Intercity buses in Germany
- Busradar ("Busliniensuche" in German) by far the best, financed by ads for BlaBlaCar (a ridesharing service) and Deutsche Bahn. It's up to you whether you want prices for those alternatives to buses to be displayed. Keep in mind that the DB fares listed on the site are always without BahnCard discount, so if you have one, you may actually get a cheaper price at the DB website. For booking, you are always redirected to the website of the bus or train company or BlaBlaCar.
- Prices can be shown in Zloty, Czech Crowns and British Pound Sterling instead of Euros.
- 9292 allows you to check and search for your connections by public transit (trains, buses, trams and metros are covered) and gives you an easy overview of the quickest, easiest, earliest and cheapest connections to your destination. The service can be taken on-the-go when offline via their app for iOS and Android.
USA
- See also: Intercity buses in the United States
Taxi aggregators
- Ride.guru - online tool that calculates potential fares for taxis, Uber, Lyft, Sidecar, Hailo, Flywheel, and Curb etc.
- Bellhop - app for Android and iOS, compares Uber and Lyft, it also provides data from other ride-hailing companies such as Juno, Curb, and Arro
- GoA2B - a taxi price comparison tool for iOS
Car rental aggregators
- AutoRentals
- QuarentaCars - compare regional and local rent a cars agencies in Spain
- Rentalcars
Other transportation aggregators
There are some aggregators that claim to compare more than one mode of transportation, often including bus, train, plane and even ferry or boat. Those are usually bad at finding the best price and you are usually better off to take their results as a first ballpark estimate rather than gospel truth. That said, they can cue you as to which companies are among those plying a certain route.
- From A to B - claims to be able to compare all modes of transport, but prices are often way off compared to more specialized websites
- Omio - train, bus, flight and ferry companies
- Rome2Rio - online multimodal transport search engine for inter-city and intra-city trip planning
- Trainline - trains in Europe; do compare with the railway websites themselves though
Hotel and hostel aggregators
Large hotels and hotel chains have a variety of rates: prepaid, flexible, corporate, discounted, etc., and they adjust their rates based on demand. Some hotels sell rooms to these booking sites at a discount. The booking companies then price in their costs to determine the price they will offer you.
Some hotel chains promise you the lowest price if you book through their website. For various reasons, many hotels consider aggregators a necessary evil at best and while you might indeed get the lowest price when booking through a certain aggregator, some hotels treat customers who booked directly through their own booking channels better, especially in terms of discretionary services not explicitly part of your contract with the hotel. Hotel owners and especially small guesthouse owners are often happy if you tell them you found them online, but came in without booking, although many hotels have higher rates for those who didn't book. Another option is to tell the hotel directly that you see a given price on a consolidator and ask them to match the price.
Hotel aggregators include:
- Hotels.com - offers one free night for every 10 nights booked
- Hostels.com - hostels and budget hotels
- Booking.com - wide selection of hotels available - you can almost always get 10 percent moneyback using link from WizzAir (you can find it when you login to WizzAir website)
- Agoda.com - specializes in Asia
- Priceline.com - allows you to set a price that hotels can try to match
- Hostelworld
- Gluten-free-hotels.com - this website is different than other aggregators because it focuses on hotels which have gluten-free menu (for people with coeliac disease & gluten intolerance)
The air travel aggregators (listed above) also do search and book hotel rooms and car rentals.