11.Ko Samui or Koh Samui, Thai: เกาะสมุย,Thai pr is an island off the east coast of the Kra Isthmus, Thailand. Geographically in the Chumphon Archipelago, it is administratively part of Surat Thani Province. Ko Samui is Thailand's second-largest island after Phuket, with an area of 228.7 km2, a population of over 63,000 and an annual tourist population of 1.5 million.Abundant tourist resources, white sandy beaches, coral reefs, and coconut trees are present on the island.