Perfect for nature lovers, Koh Mook owns a great spot for swimming and diving to see beautiful corals found around the island. The island is also home to a fisherman’s village on the east side. But the real highlight lies within. Hidden inside is a lagoon featuring emerald-like color of water. When the tide is low enough, the entrance to the lagoon is then unveiled. You need to swim into a narrow tunnel for around 80 meters until you reach the lagoon. When the sun shines, the emerald color of the water reflects onto the tunnel’s wall, and that’s where its name, Tham MoraKot (The Emerald Cave) came from. To get to the island, take the boat from Pak Meng Pier in Amphoe Sikao for the 40 minute trip. The boat rental fee is about 1,500 Baht per day. Choices of accommodations are available on the other side of the island.