The Similan Islands (Thai: เกาะสิมิลัน) is a group of islands in the Andaman Sea off the coast of Phang Nga Province, southernThailand. It is a national park which was established in 1982.

Similan Islands National Park was established after the one-year exploration by the Foresty department. The park is the archipelago consisting of nine islands which are Ko Bon, Ko Bayu, Ko Similan, Ko Payu, Ko Miang (two adjoining islands), Ko Payan, Ko Payang, and Ko Huyong. Recently, the park was expanded to included two remoted islands which are Ko Bon and Ko Tachai. The Similans are situated 70 kilometres from Phang Nga town. "Similan" is a Yawi word which means "nine". Similan is one of the most famous diving sites in Thailand.

Dive sites

The Similan national park is famous for its divesites. It has typically 2 different kind of diving. East side diving consists of gently sloping coral reefs with sandy patches and the occasional boulder in between. West side diving is known for its huge underwater granite boulders with numerous swimthroughs. Maybe the most famous east side dive site is East of Eden, off Island number 7. Elephant head rock is arguably the most famous west side dive site with a maze of swimthroughs and the reputation for spin-cycle like currents running in every direction.

Elephant head rock was named by Horst Hinrichs from Germany in the mid 70s, founder of one of the oldest dive shops in Phuket, Santana Diving.

Other popular divesites include North Point, Deep Six, Boulder City and the awesome pinnacles off Koh Bon and Koh Tachai.

The mother of all divesites in the Similans, which is actually part of Surin national park, is Richelieu Rock. Famous for its incomparable variety and abundance of marine life. Whale shark sightings are not uncommon here.

However, since 1999, its once most beautiful dive site, the Fantasy Reef, has been closed from all diving activities after its condition had significantly deteriorated. the National Park officially blames diving for the deterioration, while dive operators in the area claims that fishing boats, with or without permission, enter the national park during low season, when no dive operators are allowed in the national park.The national park also claims that the dive site suffered significant damage from the tsunami in 2004. Since noone but the national park staff is allowed to dive Fantasy Reef it is impossible to oppose to that statement, but still, The argument has been used for the government in order to extend the closure period.