Dive site · Open sea
Sail Rock
The Gulf's most famous dive, with its vertical Chimney.
Dive site · Open sea
The Gulf's most famous dive, with its vertical Chimney.
Sail Rock, or Hin Bai, is the dive the whole Gulf of Thailand talks about. It's a granite pinnacle that actually pierces the surface in open sea between Koh Tao and Koh Phangan, closer to Phangan, and from Koh Tao it's a proper day out: count on one to one and a half hours of boat each way.
The signature is the Chimney, a natural vertical swim-through inside the rock: you enter around 16 to 18 metres and rise through a shaft filled with glassfish, exiting around 12 or 6 metres. Outside, the walls drop to around 30 metres, deeper still at the base.
This is big-fish water. Huge schools of big-eye trevally wheel around the rock like weather, with chevron and yellowtail barracuda, great barracuda, groupers, batfish and morays in the mix, and the Gulf's best whale shark odds, especially from March to June and again around September and October.
Open Water divers are welcome when conditions allow, but the site rewards an Advanced certification: it's open sea, and the best of it sits deep.
In open water between Koh Tao and Koh Phangan. Koh Tao schools run it as a full-day trip a few times a week in season; skip it during the November monsoon weeks, when the crossing gets rough.