Sail Rock

Koh Phangan · Gulf of Thailand · Thailand

Sail Rock (Hin Bai) is the Gulf of Thailand's most celebrated dive site, a massive underwater granite pinnacle rising from the seabed at 30+ meters to about 15 meters above the surface. Located between Koh Phangan and Koh Tao, it stands alone in open water, acting as a magnet for marine life. The rock's signature feature is the Chimney — a vertical swim-through passage that pierces the rock, allowing divers to enter at around 18 meters and exit at approximately 6 meters, or vice versa. Swimming up through the Chimney as light floods in from above is one of the most memorable experiences in Gulf of Thailand diving. The rock's surface is covered in anemones, barrel sponges, and hard corals, supporting dense communities of butterflyfish, angelfish, and anemonefish. Massive schools of batfish orbit the rock, and barracuda hold formation in the blue. Large groupers and trevally patrol the deeper sections. Sail Rock is the Gulf's most reliable location for whale shark encounters — these gentle giants visit during their seasonal migration, with sightings peaking between March and June. Nudibranchs and seahorses reward macro photographers on every dive. The site is reached by boat from Koh Tao (90 minutes), Koh Phangan (60 minutes), or Koh Samui (90 minutes). Conditions can vary significantly — visibility ranges from 10 to 30 meters, and currents can be strong around the rock.