Sail Rock (Hin Bai)

Sail Rock emerges from the deep Gulf of Thailand like a monument, a single pinnacle rising from 40 metres depth to break the surface as a jagged rock formation visible from miles away. Below the waterline it is, by near-universal consensus, the best dive site in the Gulf of Thailand — and one of the finest in all of Southeast Asia.

The Chimney

Sail Rock’s defining feature is a vertical chimney — a narrow passage through the rock that runs from about 22 metres down to 18 metres, then opens up into a wider shaft that rises almost to the surface. Swimming through the chimney with shafts of sunlight filtering down from above, surrounded by soft corals and schooling fish, is one of the most memorable experiences in Thai diving.

The chimney is swimable by divers of any certification level — it requires no special training, just reasonable buoyancy control and the confidence to enter an enclosed space. Those who prefer can circle the outside.

The Pinnacle

The rest of the dive is equally spectacular. The walls of the pinnacle are encrusted with soft corals, sponges, and sea fans. Schools of yellowfin tuna, chevron barracuda, and enormous batfish circle the rock constantly. Whale sharks are regular visitors, particularly from March to May and in September.

At depth (30–40m), the base of the pinnacle has a sandy bottom with leopard sharks and occasional eagle rays gliding over it.

Practical Information

Sail Rock is a 1.5–2 hour speedboat journey from Koh Samui and Koh Phangan, and about 45 minutes from Koh Tao. The surface conditions can be choppy, particularly with a northeast wind, but the underwater experience is worth every minute of the crossing.

Diving is possible year-round, though the site is at its clearest from April through June. The site is exposed to current, particularly around the tip of the rock — manageable for most divers but worth noting.