Khao Sam Roi Yot is the first marine national park of Thailand, the name of park means “the mountain with three hundred peaks”, covering the area of approximately 98 square kilometers with limestone hills, mangrove swamps and beaches. The landscape is high steep limestone mountains by the beautiful coast, matching with plain area stand by the sea, which are marshy beach and shallow sea pond. There are limestones islands nearby the coast e.g., Sattakut Island, Kho Ram Island, Nom Sao Island, Rawing Island, Rawang Island and Khi Nok Island. The flat area with stagnant water through the year on the west of the park is Thung Sam Roi Yot, which is the large freshwater marsh, covering around 36.8 square kilometers.