Also known as Koh Muk, this stunning island paradise in the Andaman Sea is far less touristy than its neighbours such as Koh Phi Phi and Phuket, and that is what makes it so special. With postcard-perfect beaches, dense jungle, limestone cliffs, and even caves to explore, it's the kind of place you come for a day and end up staying a week. The biggest Koh Mook attraction, and the spot that put Koh Mook on the map for many tourists, is the stunning Emerald Cave. Only accessible by boat, you get to the Cave by swimming through a narrow chamber in the sea at the bottom of a cliff. You end up in a lagoon with a small sandy beach. It's the kind of scene you'd expect to find in a movie, and it really is a spectacular spot.