Sail Rock · Koh Tao
Two dives. Open ocean. A vertical chimney swim-through and clouds of fish. This is Sail Rock — the Gulf of Thailand's most legendary dive site, every Friday with La Bombona Diving.
Halfway between Koh Tao and Koh Phangan, a lone granite pinnacle rises from the deep — no reef around it, just open ocean and one of the richest dive sites in Southeast Asia. Sail Rock is famous for its vertical chimney: a natural swim-through you enter at 18 metres and exit at 6, surrounded by rock on all sides.
Expect huge schools of trevally, barracuda and batfish, big groupers, and — in season — whale sharks. With two guided dives in small groups, you'll explore the site safely and fully. Open to all certified divers, though Advanced certification is recommended.
Trips run every Friday — book ahead to secure your spot. Not included — mandatory dive insurance (100 THB).
Book your spotYour Journey
Meet the La Bombona team at the boat, gear up, and head offshore before the wind picks up. Breakfast is served on the way out — a good time to go over the dive briefing with your guide. The crossing takes around an hour depending on sea conditions.
Descend onto the pinnacle with your guide, to a typical depth of 18–30 metres depending on your experience level. Expect trevally schools, barracuda, big groupers and clouds of fusiliers, with around 45–55 minutes underwater — and your first shot at the famous chimney swim-through.
Rest, rehydrate, and swap stories on the deck while snacks circulate. Your guide will share observations from the first dive and brief you on the second — often the better dive of the two, once you know what to look for.
Explore a different section of the site, or return to the chimney with fresh eyes and more time at depth. Keep your eyes open — whale shark encounters, when they happen, often come on the second dive.
Lunch is served on the boat heading back — time to reflect, rest, and plan your next underwater adventure. We arrive back in Koh Tao at around 1:00 pm.
No crowded day-trip boats. The trip to Sail Rock runs on our private fast boat, built for small groups — space to gear up with ease, breakfast on the way out, lunch on the way home, and a deck to relax on during the surface interval.
Insights from our divers
I had an amazing Try Dive experience at La Bombona! I was quite nervous and even panicked a few times during the first dive, but Armand was incredibly calm, patient and reassuring. He took the time to make me feel comfortable.
I returned to La Bombona after doing my Open Water here in April, to do my Explorer 30, Deep 40, and Nitrox courses. I had Vasco as my instructor, and he was fantastic. He was extremely knowledgeable on scuba diving techniques and theory.
We had a blast doing our open water course with Carlo and Intza! With no previous diving-experience, the whole crew made us feel both welcome, comfortable and safe throughout the whole experience. Really cool and professional people.
Amazing diving experience. The staff (Carlo Rossi) was very professional and explained the theory with the detail that was easy to understand.
Great dive shop! Me and 3 friends came to Koh Tao with me and 1 friend doing an open water, 1 friend doing advanced open water and 1 friend doing fun dives. Each of us had incredible experiences in our respective courses.
Big thanks to La Bombonera Diving School and my outstanding instructor Martin for this fantastic opportunity to learn a new skill and discover the underwater world! The whole team is incredibly welcoming and friendly.
Yes. Sail Rock is a certified-diver-only trip. Open Water certification (or equivalent) is the minimum. An Advanced certification is recommended, as the site sits in open water and the best of it lies below 18 metres. If you're unsure whether your current level is suitable, just ask us before booking.
Sail Rock's signature — a natural vertical swim-through inside the pinnacle itself. You enter at around 18 metres and ascend through the rock, exiting at 6 metres. It's wide enough to be comfortable, and your guide will lead the way.
Our Sail Rock trips run every Friday, departing around 05:45 from Koh Tao and returning to the island at around 1:00 pm. Times may vary slightly depending on sea conditions — your guide will confirm exact timings when you book.
Nothing diving-related — all equipment is included in the package price. Bring reef-safe sunscreen, a light layer for the boat, a towel, and any personal items you need for a morning out on the water. We take care of the rest.
If it has been more than 12 months since your last dive, we recommend completing our Refresh Course first. It takes one day, gets you comfortable back in the water, and means you can actually enjoy Sail Rock rather than spending the dive getting reacquainted with your gear.
Whale shark sightings do happen at Sail Rock, most often around March–May and September–October. They are never guaranteed — these are wild animals in open water — but Sail Rock is one of the most reliable spots in the Gulf of Thailand for an encounter. Your guide will brief you on behaviour protocols if a sighting occurs.
We understand that travel plans change. Get in touch via WhatsApp to discuss your booking and any changes you need to make. We'll work with you wherever possible.
Prefer to check availability first? Send us a message on WhatsApp and we'll get back to you as soon as possible. Friday spots fill up fast.
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