Koh Tao is an island in Thailand and is part of the Chumphon Archipelago on the western shore of the Gulf of Thailand. It covers an area of about 21 km2. Administratively it forms a district of Surat Thani Province. As of 2006 its official population was 1,382. The main settlement is Ban Mae Hat. The economy of the island is almost exclusively centered on tourism, especially scuba diving.