In the northern Similan Islands, the dive sites of Koh Bon, Koh Tachai, and Richelieu Rock are renowned for their significant oceangoing sightings. Richelieu Rock, in particular, attracts large numbers of whale sharks and manta rays during the diving season. MV Marco Polo, Junk, and Thailand Aggressor offer liveaboards to these dive sites.
Day boats operate year-round to dive sites in southeastern diving in Phuket. The stunning waters around Koh Phi Phi offer many excellent diving sites, making Phuket an ideal base for a shore diving holiday. Koh Dok Mai is a vertical wall, 30m high, covered with colorful crinoids. Another popular day boating spot, Shark Point, is named after the leopard sharks that live there. Anemone Reef is one of the most popular day trips from Phuket. This dramatic drop has been officially designated a marine reserve and offers terrific diving.
The Similan Islands are located 100 kilometers northwest of Phuket and are best joined for liveaboard diving from Phuket. With snow-capped beaches set against picturesque granite cliffs and spectacular diving spots in crystal clear waters, it’s no surprise that the Similan Islands are ranked as one of the world’s top diving destinations.
Declared a national park in 1982, the Similan Islands consist of nine islands and many smaller rocky outcrops running roughly north-south. Please note that these islands are a seasonal destination, and diving is only available from November to April each year.
Similan Island Itinerary Dive Sites
Almost all of the nine islands that make up Similan are surrounded on their western flanks by massive underwater rock formations that have been eroded by ocean erosion over thousands of years. These boulders are home to numerous marine life and offer divers the opportunity to swim through passages, caves, and canyons.
The eastern side of the Similan Islands is home to lush coral reefs, some 500 species of hard and soft corals, and an astonishing array of marine life, including leopard sharks, guitar rays, and manta rays.
Koh Bon is an island located 18 kilometers northeast of the Similan Islands. The reef-surrounded western end of Koh Bon is famous for the manta rays that can breed on the island. Whale sharks are also occasionally spotted near Koh Bon. D divers may encounter schools of jacks and tuna, marble rays, and leopard sharks down the West Ridge. Schools of yellow snapper and oriental sweetlips fish return to the shallows, making Koh Bon one of Thailand’s top dive sites.
Koh Tachai is located north of Koh Bon.
Richelieu Rock is an underwater mountain 12 kilometers east of the Surin Islands. At low tide, only one-meter-high rocks appear above sea level. Below sea level, the dive site leads to one of the best dive sites in the world. There are schools of barracuda, bigeye trevally, and batfish on the top of the cloud. Sergeant Major, Long Nosed Emperor, Snapper, Rainbow Runner, and Cobia add extra color to the dive. Giant potato cod, marble rays, and schools of more than two hundred blue-spotted rays are often seen.