Richelieu Rock is one of the most famous dive sites in Thailand. Located 10 miles east of Koh Surin Tai, Richelieu Rock is a remarkable pinnacle rising from a depth of 40 meters. This spectacular dive site attracts the largest fish in the world, often spotted here in March and April – the whale shark.
There are various versions of how Richelieu Rock got its name, but the most credible would be the one concerning the diving pioneer, Jacques-Yves Cousteau. The discovery was helped by the local fishermen and gave rise to the reputation of Richelieu Rock as a recreational scuba dive site. One can see the very top of the rock during low tides, but it is fully submerged at high tide. The surface below Richelieu Rock is a horseshoe-shaped reef which consists of groups of rocks and pinnacles. The iconic dive site can be accessed by diving boats or speedboats that usually send passengers for day trips.
Diving can be carried out at a depth of around 20-28 meters, although maximum depth is at 35 meters. As there are currents that constantly sweep the pinnacles, there are not many hard corals to be found, but there are plentiful soft corals to be seen. Beautiful purple corals are the main attraction here. The nutrient-rich waters make the plankton bloom, which attracts large pelagic, including whale sharks and manta rays. A bountiful marine life surrounds Richelieu Rock year-round, where visitors often encounter large schools of barracuda, fusilier, and snapper. This superb biodiversity is what contributes to Richelieu Rock’s reputation as Thailand’s favorite dive site and a popular liveaboard diving destination.