Koh Mook (Mook Island) is an island in the Southern Andaman Coast region of Southern Thailand which is the location of the Tham Morakot (Emerald Cave). The name of the cave means Emerald Cave. It describes the emerald color produced by sunlight filtered through sea water. Inside the cave is a secluded beach of white sand. Tham Morakot is visited by swimming or by small boats to pass through during low tide along the channel of 80 meters long. You can swim, snorkeling, sunbathe, see the coral, see colorful starfish, and see many kind of fish.Which is the island's underwater wedding of Trang.