North of Samui between the islands of Koh Tao and Phangan is the internationally renowned dive site of Sail Rock.
Although only 15 meters above the water, the structure extends 40 meters below the surface.
The main attraction of Sail Rock is a naturally formed 15-meter high underwater dive wall or chimney.
Divers can ascend from 18 meters up the chimney wall to the surface, making this a unique diving experience.
Visibility is usually excellent at around 30 meters.
The structure itself is pocked with small holes which are ideal homes for white-eyed and yellow margin moray eels, as well as large sea anemones. Sightings of reef sharks and manta rays are also common, as are large schools of tuna, jacks, trevellys and barracudas.
During the winter months whale sharks can occasionally be seen.