About 90 minutes from Chalok Bay, Sail Rock is the Gulf of Thailand’s most famous dive.

The pinnacle rises straight up from the seabed, covered in coral and buzzing with life. You can swim up the famous “Chimney”, a vertical tunnel inside the rock, and be met by huge schools of barracuda, trevally, and fusiliers outside.

It’s a big, busy site where there’s always something happening, and one of the best chances in the region to spot a whale shark in Koh Tao.