The Similan Islands (Thai: หมู่เกาะสิมิลัน, Thai pronunciation: [mùː kɔ̀ʔ si.mi.lan], Malay: Pulau Sembilan سمبيلن ڤولاو) is a group of islands in the Andaman Sea off the coast of, and part of, Phang Nga Province, southern Thailand. It is a national park which was established in 1982.
Similan Islands National Park was established after a one-year exploration by the forestry department. The park is an archipelago consisting of nine islands named 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 include two remote islands named Ko Bon and Ko Tachai. The Similans are situated 70 kilometres from Phang Nga town. "Similan" is a Yawi word which means "nine".
Ko Similan is the largest island. There are a total of 9 islands. The sea in the area has an average depth of 60 feet. Underwater it is full of rock formations and coral reefs in several shapes and forms, resembling such things as deer, leaves, brains, and mushrooms.