Day 5: The 4 islands tour from Koh lanta was the highlight of the trip. It took us to 4 islands – Koh Ngai, Koh Kradan, Koh Mook and Koh Chueak in a long tail boat. We stopped at two locations for snorkeling. It was a bit disappointing snorkeling experience but the highlight of the tour was swimming 80 meters through the Emerald cave in Koh Mook island. It was pitch dark and the guide helped us find the way while swimming. After swimming, you come on the other side - a beautiful beach pond with cliffs one side and forest on other.