You can not miss this day trip! After 40 min the boat will take you to the uninhabited Ko Mook island and after swimming through the cave (50 m) you will be astonished at the famous Emerald Cave Lagoon which is in the middle of the island.(You will be given a safety jacket and a torch, all is under the control of an experienced local guide). There is no other way how to get to the lagoon as it is surrounded by steep rocks. You will be served drinks and fruit at the boat. You can do this trip by your private boat (8.000 THB/boat).