Located on the west side on Koh Mook. Visits to the cave must float in groups from the mouth of the cave. Through the darkness, a distance of 80 meters, at the mouth of the cave, sunlight reflects on the water in the cave, making the water look emerald green. The other side is a large cavern. Inside, there is a white sandy beach surrounded by sheer cliffs and illuminated by light. Hat Chao Mai National Park will close tourism around Koh Mook. To restore nature from June 1 to September 30 of every year, travel can charter a boat from Pak Meng Pier, Sikao District, takes 40 minutes or buy a day trip package from Tour Operators in Pak Meng Pier Area You can also rent a boat from Khuan Tung Ku Pier, Kantang District, to visit the Emerald Cave.