Koh Mook is a large island comparing with nearby islands but little smaller than Koh Libong. It is well known as the owner of Morakot Cave. Koh Muk is virtually more interesting for its beautiful beaches of fertile natural surroundings. It is the island of ancient communities mostly Muslim. Villagers normally use long-tailed boats to travel between the island and Kuan Tung Ku Pier taking only about 15 minutes.