Koh Tao, Thailand

Koh Tao is a 21-square-kilometer island in the Gulf of Thailand, home to approximately 2,500 permanent residents. Used as a political prison until 1947, the island later transformed into one of Southeast Asia's principal centers for scuba diving education. Coral reefs rim shallow bays such as Tanote Bay and Shark Bay, providing habitats for green sea turtles and reef sharks. Just off the northwest shore, the sandbar of Koh Nang Yuan links three small islets accessible by longtail boat. Visitors climb to granite lookouts like John-Suwan viewpoint, explore coastal coves, and undertake open-water diving courses.