The star attraction of Koh Muk, Morakot Cave (Emerald Cave) looks at first glance like little more than a hole in the base of a cliff. Intrepid travelers who can brave the 260-foot (80-meter) swim through a dark and narrow entrance tunnel will emerge into a hidden lagoon where the sunlight shines down, illuminating the water and giving it its signature emerald color. The main hall of the cave is actually a sinkhole with a small sandy beach to one side, backed by lush greenery.
Before Morakot Cave became the tourist attraction it is today, it was said to be a favorite spot for pirates to stash their treasure. Later, locals stumbled upon the lagoon while foraging for swallows’ nests to make Chinese bird’s nest soup.
Morakot Cave can only be visited when the tide is low enough to reveal the entrance. It can be dangerous to attempt to reach the cave alone, so having a knowledgeable guide is critical.