Another of the things you should not miss in the Phi Phi Islands if you are a certified diver, is a diving tour. Thailand's Andaman Sea is a paradise underwater as well. Moray eels, sharks, tropical fish, turtles, the list of animals you may see is almost endless.
The main diving sites are King Cruiser, Shark Point, koh Ha, Hin Daenh, Hin Muang, Bida island, Phi Phi Leh and Gerang Heng.