Hin Daeng and Hin Muang are situated to the south of Koh Phi Phi, approximately 25 kilometers south west of Koh Rock. Both Hin Daeng (red rock) and Hin Muang (purple rock) are perhaps the best sites in Thailand.
Hin Daeng is seen as a rock protruding about three meters above the surface but underwater the rock is huge. To the south it descends straight down to over 60 meters forming the most radical vertical drop in Thailand seas.
The wall is dotted with light growths of soft corals and a few sea fans, with an eastern slope with two long ridges that descend into the blueness where it is possible to swim along these ridges down to 40 meters or more.
There is a vast quantity of soft coral along these ledges and a huge diversity of marine life including barracudas, tuna, groupers and of course many different species of reef shark, especially the gray reef shark which can be seen large groups of up to ten. It is an extremely exhilarating sight.
Hin Muang is a completely submerged pinnacle also abundant with a huge variety of marine life. The name comes from the thick purple growth of soft corals that are found here. The pinnacle is about 200 meters long, and narrow with steep, vertical sides and a rounded top.
There are many large sea fans including red, white and orange, with a huge covering of anemones and clown fish at the top. There is also a good chance of seeing whale sharks and manta rays here and the visibility can be up to 50 meters or more!