Ko Samui (also known as Koh Samui, Thai: เกาะสมุย, Thai pronunciation: [kɔ̀ʔ samǔj] or simply Samui, as it is referred to by locals), is an island belonging to Surat Thani Province, off the east coast of the Kra Isthmus in Thailand, close to the town of Surat Thani on the mainland. It is Thailand's third largest island, with an area of 228.7 km2 and a permanent population of approximately 55,000 (2008).