Dive Site: Sail Rock

About Sail Rock

Sail Rock, known as Hin Bai in Thai, stands as the premier dive site in the Gulf of Thailand, located strategically between Koh Phangan and Koh Tao. This isolated pinnacle rises dramatically from the seafloor at 40 meters, piercing the surface by about 10 meters, creating a unique and self-contained ecosystem. Its position in a deep channel ensures a constant flow of nutrient-rich currents, making it a biological hotspot that attracts an incredible array of marine species. The rock's topography offers diverse habitats, from shallow shelves around 5-6 meters, perfect for juvenile fish and anemones, to vertical walls and deeper sandy slopes stretching beyond 30 meters. This varied depth profile supports a wide range of marine life, from vibrant coral formations and sponges to large pelagic predators. The site is particularly famous for its signature vertical swim-through, "The Chimney," which offers an exciting ascent from 18 meters to 6 meters, surrounded by schooling fish. Divers at Sail Rock can anticipate encountering massive schools of barracudas, trevallies, and fusiliers, which often form swirling tornadoes of silver. The site is also renowned for frequent whale shark sightings, especially during peak plankton blooms. The combination of its unique structure, strong currents, and abundant food sources makes Sail Rock an exhilarating dive destination for both experienced and advanced divers looking for dynamic underwater encounters. Access to Sail Rock is typically via boat trips, with shorter travel times from Koh Phangan and longer journeys from Koh Tao or Koh Samui. Despite its popularity, the sheer size and diversity of the site ensure that every dive offers new discoveries. The conditions here, ranging from mild to strong currents, offer an engaging challenge and a rewarding experience for those ready to explore this underwater marvel.

Dive site facts: Sail Rock

Depth

5–40 m

Current

Mild to strong, variable

Visibility

10–25 m

Water temperature

27–30°C

Entry

Boat

Level

Advanced recommended, Open Water with experience

Dive type

Wall, pinnacle, pelagic

Region / port

Gulf of Thailand

Coordinates

9.7234, 100.0567

Conditions & Currents

Sail Rock is situated in open water within a channel that generates consistent open-water currents, ranging from mild to strong depending on the day and specific location around the pinnacle. These currents are a primary reason for the site's rich marine life, pushing nutrients and plankton upwards. Divers should be prepared for variable current conditions, which can be particularly noticeable on different sides of the rock. Entry is always by boat, and negative entry might be necessary on days with stronger currents to quickly reach the shelter of the pinnacle. Exiting the dive will also require careful planning with your guide, often involving a surface swim or being picked up by the boat after deploying an SMB. Due to these dynamic conditions and the potential for strong currents, an Advanced Open Water certification is recommended, and divers should have prior experience managing cur

Marine life & sighting chances

Whale shark

March–September · occasional

Barracuda (Chevron and Pickhandle)

common

Bigeye Trevally

common

Batfish

common

Malabar Grouper

common

Honeycomb Grouper

common

Moray eel

common

Snapper

common

Fusilier (Yellowtail)

common

Sea anemone

common

Anemonefish

common

Nudibranch

common

Wart slug

common

Scorpionfish

occasional

Dive profile & how the dive runs

Your dive at Sail Rock typically begins with a descent along the main pinnacle, often entering on the sheltered side depending on the current. The dive plan usually involves circumnavigating the main rock, exploring its vibrant walls covered in soft corals and sponges. A highlight is the vertical swim-through known as "The Chimney," with an entrance at 18 meters and an exit at 6 meters, showcasing groupers and soldierfish within. After exiting, you can explore the shallower parts of the pinnacle, which are rich with anemones and schooling juveniles. Divers often venture to satellite pinnacles found to the south, east, and west of the main rock, which extend to depths of 30-40 meters, offering opportunities for deeper exploration and spotting larger pelagics in the blue. The turn point for your dive will be based on air consumption and no-decompression limits, allowing ample time to ascend slowly and complete a safety stop at 5 meters, often surrounded by a multitude of schooling fish near the main rock or an SMB deployment in open water if currents are strong.

Underwater photography

Sail Rock offers fantastic opportunities for both wide-angle and macro photography due to its diverse marine life. For wide-angle shots, a fisheye or wide lens is essential to capture the scale of the pinnacle, the massive schools of barracudas and trevallies, and any passing whale sharks. Pay attention to positioning yourself against the current to allow the fish schools to engulf you for dramatic shots. For "The Chimney" swim-through, a wide lens is also beneficial, and consider using artificial light to illuminate the interior and bring out the colors of the corals and crustaceans. For macro enthusiasts, explore the cracks and crevices of the rock walls for nudibranchs, wart slugs, shrimp, and camouflaged scorpionfish; a macro lens and strobes will be crucial here. Buoyancy control is paramount, especially within "The Chimney" and when currents are present, to avoid disturbing the delicate marine ecosystem and to maintain stable shots.

Combine with nearby dive sites

• Chumphon Pinnacle

  Chumphon Pinnacle is a renowned deep dive site situated approximately 12 kilometers northwest of Koh Tao in the Gulf of Thailand.

• Shark Point

  Shark Point is an exceptional dive site located within the highly protected Jardines de la Reina Marine Park off Cuba's southern coast.

• Koh Tao — Japanese Garden

  Japanese Garden is Koh Tao's premier shallow reef dive site, located in a sheltered bay on the eastern side of Koh Nang Yuan island.

• Koh Tao — Twins

  Twins, a highly popular dive site near Koh Tao, Thailand, is renowned for its accessibility and rich marine life.

• Koh Tao — Green Rock

  Green Rock, situated off the west coast of Koh Tao near Koh Nang Yuan, is a unique dive site characterized by a striking cluster of granite…

Getting there & logistics

Sail Rock is most frequently accessed from Koh Phangan, which is the closest island, with boat trips typically lasting about an hour each way for a half-day excursion. From Koh Tao, it's a slightly longer journey of 1.5 to 2 hours, usually organized as a full-day, two-dive trip including lunch. Although Koh Samui is further, operators often use speedboats to make the travel time comparable to Koh Tao, though this tends to be the most expensive option. Most dive centers include all necessary fees in their package price. It is common for liveaboards and day trips from these islands to combine Sail Rock with other local dive sites, although its isolated nature often means it's the primary focus of a dedicated trip. There are no specific marine park fees for this site.

Safety & environment

Diving at Sail Rock requires careful attention to safety protocols due to potentially strong and variable currents. Always listen to your dive guide's briefing regarding current conditions and entry/exit procedures. Ensure you are comfortable with drift diving and maintaining excellent buoyancy control, especially if attempting "The Chimney" swim-through. Carrying an SMB (Surface Marker Buoy) is highly recommended for signaling the boat, particularly if you surface away from the main pinnacle. The nearest recompression chamber is located in Koh Samui, so evacuation in a dive emergency can be time-consuming. It is crucial to have comprehensive dive insurance that covers emergency medical treatment and evacuation. Always dive within your training and comfort limits, and communicate any concerns to your dive leader before and during the dive.

Who it suits — and who it doesn't

FAQ

Sail Rock FAQ

Liveaboards diving Sail Rock

These liveaboards may visit Sail Rock on selected itineraries — the exact dive sites depend on departure, weather and conditions.

Mandarin Queen 9

Thailand

26 guests37.5 m

Manta Queen 8

Thailand

24 guests

$127/day

The Junk

Thailand

18 guests33 m

$163/day

Deep Andaman Queen

Thailand

23 guests30.5 m

$194/day

Explorer

Thailand

16 guests25 m

$150/day

Andaman

Thailand

20 guests26 m

$108/day

Stingray

Thailand

8 guests24 m

$245/day

Seatopia

Thailand

24 guests24 m