Diving Thailand

Richelieu Rock, Koh Tachai and Koh Bon

The famous stretch of Andaman Sea lying between the Similan and Surin Islands is well renowned as whale shark liveaboard safari territory. It lies immediately to the north of the Similan Islands and covers Koh Bon in the south, up to Koh Tachai, and finally northwards on to Richelieu Rock.

Although there are many sites in Thailand for diving with whale sharks, Richelieu Rock stands proudly at the top of the list. The surrounding deep sea upwellings of nutrient-rich water make for excellent diving where plankton blooms attract many fish, most notably, the biggest one of all.

Richelieu Rock is a large dive site that can be dived several times over without covering the same area. This aspect, plus the superb bio-diversity it boasts, makes Richelieu Rock on of Thailand's top dive sites and a favourite on the liveaboard itineraries.

Highlights

Richelieu Rock - This site consists of a huge central pinnacle surrounded by smaller jutting rocks every inch of which has been colonized by something: soft corals, anemones, barrel sponges and sea fans. In addition to the possibility of swimming with whale sharks you can also look forward to the likes of manta rays, barracudas and huge groupers. All of this before you even begin to explore the fascinating smaller creatures lurking in every nook and cranny.

Koh Tachai - This site is often visited en route to Richelieu Rock from the Similans and is in fact an island which has several nearby dive sites. Koh Tachai Plateau is the best known of these and as the name suggests is a submerged plateau of hard corals and boulders. Typically of the area there are swim-throughs and channels all over the place. The larger fish include manta rays and leopard sharks and if the whale sharks are not at Richelieu Rock they may well be here.

Koh Bon - As well as Koh Tachai, Koh Bon is part of the Similan Island national park and is only an hour or so away from the Similans so it is worth special mention as one of the best dives sites in Thailand for manta rays. In addition to mantas there are also frequent appearances by leopard sharks, eagle rays and black tip reef sharks. The Koh Bon area is not, however, only about pelagics since critters are numerous and varied which makes night diving here exceptional.

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How to Dive Richelieu Rock

Diving at Richelieu Rock and Koh Tachai and Koh Bon islands is best done by liveaboard and most of the dive cruise operators include these sites in their itineraries.

Whether you wish to dive here as part of a long dive liveaboard taking in the Similans and maybe even Burma or as a short trip (minimum of 4 nights) you will find the itinerary that suits you in our Thailand liveaboards section.

Diving Season

Diving in Richelieu Rock is limited to the months from October until early May, when the conditions are usually excellent and all the liveaboards visit regularly.

Reef Summary

Great for: Large animals, small animals, underwater photography, dive value-for-money and advanced divers
Not so great for: Wrecks, beginner divers, snorkelling, non-diving activities
Depth: 5 - 35m
Visibility: 15 - 35m
Currents: Can be strong
Surface conditions: Can be rough
Water temperature: 26 - 29°C
Experience level: Intermediate - advanced
Number of dive sites: 2
Distance: ~145-200 km north of Phuket (7-10 hours), 40-80 km north west of Khao Lak (3-4 hours, or 1-2 hours by speed boat)
Access: Liveaboard trips only
Recommended length of stay: 3 days

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