Richelieu Rock is a world-famous dive site. It belongs to the National Marine Park of the Surin Islands. The diving here is cited in many top ten dive sites of the world lists. Diving on Richelieu Rock is either done on a day boat, out of Khao Lak, or on a liveaboard boat from Khao Lak or Phuket; there are boats now sailing from Ranong too.
This site is in a Marine Protected Area. To dive at Richelieu Rock you will have to pay a National Marine Park Fee to the Surin Islands.
The site was likely named after General Richelieu, a commander in the Royal Thai Navy. He was the first person to complete a hydrographic survey of the Andaman Sea and Navy maps from the early 1900s mention Richelieu Rock.
The maximum depth of this dive site is about 33 m (108 ft).
Richelieu Rock is the top of a huge seamount. It surfaces only a few meters with low tide and is practically invisible from the surface during high tide.
Water temperature at Richelieu Rock varies from about 26 to 30 °C (79 to 86 °F).
When entering the water here for diving, please take care for currents, which can be moderate to strong, especially at the surface. People who need a longer time to descend should look for a good quiet day.
The slopes of Richelieu Rock are covered with a lot of purple soft corals. Divers have common sightings of whale sharks and manta rays during the dive season. Also sometimes guitar rays can be seen here. In between the corals live moray eels as well as smaller animals like porcelain crabs, harlequin shrimps, ghost pipe fish, sea horses, and nudibranches.
Although the dive site is huge, you will be able to see most of the landscape of the whole site within one dive. However, there is so much too see here. You can easily make dozens of dives here and still have the feeling that you want to return.
On the reef are scorpion and stone fish, which have very good camouflage. Don't touch anything here, you might mistake a rock for one of those fish.
Exiting water can be demanding due to common high waves. Because Richelieu Rock is a famous dive spot, visited by many divers throughout the dive season, it is very important that the divers stick to the rules of the National Marine Park. Or in other words: Look only with your eyes and leave nothing but bubbles.
An inflatable marker buoy is recommended, especially if currents are strong.