Emerald Cave (Tham Morakot)

Emerald Cave, also known as Tham Morakot, is a sea cave located on the island of Ko Muk (Koh Mook) in Trang Province, Thailand. It sits along the Andaman Sea coast and is a major tourist destination for island hoppers. The cave is only accessible from the water.

Access requires swimming or kayaking through a narrow, partially submerged tunnel that is pitch black for about 80 meters. Visitors must time their entry with the tides, as the tunnel is completely impassable during high tide. Tour guides use waterproof flashlights to lead groups safely through the darkness.

After swimming through the dark tunnel, visitors emerge into a collapsed interior chamber that features a hidden, completely enclosed lagoon. The lagoon is surrounded by towering limestone cliffs and features a small, pristine white sand beach. Sunlight streams in from a hole in the ceiling, illuminating the space.

The cave gets its name from the striking, bright emerald-green color of the water inside the enclosed lagoon. This brilliant color is caused by sunlight reflecting off the white sandy bottom through the clear Andaman Sea water. The contrast between the dark tunnel and the glowing lagoon is spectacular.