Richelieu Rock, located in the Andaman Sea near the Surin Islands, is widely regarded as the best dive site in Thailand and one of the top scuba diving destinations in the world. First discovered by Jacques Cousteau, this legendary limestone pinnacle is famous for its colorful soft corals, incredible marine biodiversity, and seasonal encounters with whale sharks.
For divers exploring Thailand by liveaboard, Richelieu Rock is an absolute highlight – offering multiple world-class dives in a single day.
Richelieu Rock offers a unique combination of vibrant coral reefs, rare critters, and big pelagic species, making it suitable for both macro photographers and divers seeking thrilling encounters.
Stunning Soft Corals & Marine Life
The reef is covered in red, purple, and pink soft corals, along with healthy hard corals. Divers can spot ornate ghost pipefish, seahorses, frogfish, harlequin shrimp, nudibranchs, and hundreds of reef fish species.
Pelagic Encounters
Richelieu Rock is world-famous for its chance of whale shark sightings during the dive season (February–April). Manta rays, barracuda, and trevallies are also common visitors.
Huge Dive Site with Endless Variety
With depths ranging from 5–40m, Richelieu Rock offers enough diversity to keep divers coming back for multiple dives in a single liveaboard trip.
Depth: 5 – 40m (16 – 131 ft)
Temperature: 25 – 29°C (77 – 84°F)
Visibility: 6 – 20+ m (can vary with plankton blooms)
Currents: Medium, but shelter is available behind pinnacles
Surface: Can be choppy due to exposed offshore location
Even on days with low visibility, the site remains spectacular – plankton blooms often attract whale sharks and manta rays.
The official Richelieu Rock dive season is October 15 – May 15.
Peak Conditions: November – April
Best for Whale Sharks: February – April
The site is closed from mid-May to mid-October to protect marine life and because of the southwest monsoon.
Richelieu Rock lies in the Andaman Sea, close to the Surin Islands National Park and about 200 km northwest of Phuket. Its isolated location means it is only accessible by liveaboard diving trips or full-day speedboat excursions. Surrounded by deep water, nutrient-rich currents bring in an incredible variety of marine life, making Richelieu Rock one of the most biodiverse dive sites in Thailand.
Minimum: PADI Open Water (or equivalent) with 20+ logged dives
Best for: Advanced divers & underwater photographers
Due to its depths and strong currents, Richelieu Rock is recommended for divers with some experience. Beginner divers may join with guidance, but the site is most rewarding for intermediate and advanced divers.
Most divers visit Richelieu Rock as part of a Thailand liveaboard diving trip that also includes the Similan Islands, Koh Bon, and Koh Tachai. Liveaboards allow multiple dives at Richelieu Rock over consecutive days, maximizing your chance to encounter whale sharks and rare critters.
Day trips are possible from Khao Lak or Ranong, but a liveaboard cruise gives you more time and the best chance of experiencing everything Richelieu Rock has to offer.
Thailand’s #1 dive site, discovered by Jacques Cousteau
Chance to see whale sharks & manta rays
Stunning soft corals in purple and red
Rare critters like ghost pipefish, seahorses, harlequin shrimp
Part of Surin Islands National Park
Accessible only by liveaboard or day trip boat