Advice for diving Similan Islands in Thailand

The Similan Islands and the surrounding National Park is famous for its world-class dive sites. There are two distinct types of topography that divers will notice. Diving in the east reveals gently sloping coral reefs interspersed with sand patches and boulders. The west is well-known for the large underwater granite boulders, dramatic scenery, and interesting swim throughs.

Each of the Similan Islands has a name and number. They are: Koh Ba Ngu (9), Similan (8), Payu (7), Miang (4, 5 and 6), Payan (3), Payang (2), and Hu Yong (1) running from north to south. Hin Pousar is called number 6 by some. Koh Bon is also part of the Similan National Park and some consider it to be number 10. Divers will get to visit a good selection of the sites if diving from one of the many liveaboards, however, day trip divers can reach these dive sites by speedboat too. A liveaboard dive trip is highly recommended to make the most of this diving destination.

In the Similan Islands, the environmental conditions are highly conducive for coral growth. More than 200 species of hard corals have been identified, and these islands are said to have the greatest abundance of reef fish in Thai waters. The water temperature averages 28 Celsius and the visibility is exceptionally clear - often exceeding 40 meters.

The Similan Islands have something to interest everyone underwater: coral-covered walls, huge boulder formations, sea fans and sponges, caves, and lots of swim throughs. Snorkellers are well-catered for with plenty of shallow coral garden areas that sit in 6 meters of water. The sandy sea floor around the islands averages 30-45 meters in depth and the channels in between the islands reach down to 70-80 meters.

There is a striking difference in underwater topography and marine systems on each island when you compare the east-side dive sites to the west-side dive sites. On the western side of the islands, the huge granite boulders are the main attraction; they have created archways, cool swim throughs and stunning dropoffs. The boulders are completely coral encrusted and a haven for marine life. The east-side of the islands boast sloping hard coral gardens that taper off between 30-40 meters. The diverse coral growth and nutrient rich waters attracts large schools of tropical reef fish - sightings of sharks and whale sharks are not uncommon.

There are over 20 dive sites within the Similan Islands National Park and all highly enjoyable. Elephant Head Rock on Koh Similan is one of the most well-known sites. It is named after the unusual shape of the group of rocks that jut out of the water. The stunning site boasts a maze of swim throughs that create tumultuous currents around the rocks. Black and white tip reef sharks, batfish and trevally are common sightings.

One of the most famous dive sites in the Similans is Richelieu Rock. This is actually part of Surin National Park, however, it is regularly visited by all the dive operators. Whale shark sightings are common, and the sheer abundance and diversity of marine life is unbeatable. Sea horses, morays, barracuda, harlequin shrimp and nudibranchs are some of the marine life highlights at this dive site.

The Koh Bon Pinnacle site is actually two submerged pinnacles that rise up from between 30-40 meters to a minimum of 12 meters below the surface. Eagle rays, leopard sharks, blue fin trevally and jack tuna can be seen here, as you dive in a figure of eight around the pinnacles.

Another fabulous dive is Koh Bon West Ledge. A ridge juts out from the island and drops away to the sea floor at 30 meters. Divers will experience some serious currents sweeping past, but you have plenty of time to find a place to hold/hook on and watch the stunning display of manta and eagle rays swim overhead feeding. A site not to be missed!

Christmas Point, on Koh Bangru, is much loved by divers for the series of dramatic archways and swim throughs. Large schools of blue fin trevally and jack tuna accompany the occasional sighting of reef sharks.

Other popular dive sites include East of Eden, North Point, Deep Six, Tachai Reef/Leopard Shark Reef and Boulder City.

Dive Site Map