HunterRescue Diver · 45 logged dives · Dived in April 2025
Amazing dive!
Barracudas and 40m+ visibility
- Saw
- Barracuda
Boat dive · Big animals · Coral · Drift · Wall
Sail Rock
Sail Rock, known to Thai crews as Hin Bai, is a lone granite pinnacle that breaks the surface roughly midway between Koh Tao and Koh Phangan, reached by boat on a full-day trip.
Also called Hin Bai, Hin Ngam, Sail Rock Koh Tao/Koh Phangan, Sail Rock Pinnacle, הין באי, סייל רוק, หินใบ, เซลล์ร็อค
10.0Diver reviews1 reviewAmazing dive!
- Depth
- 0-40 m
- Level
- Open Water
- Visibility
- 17–26 m
- Water
- 28–31 °C
- Entry
- Boat dive
The verdict
A good dive, worth a day.
Sail Rock, known to Thai crews as Hin Bai, is a lone granite pinnacle that breaks the surface roughly midway between Koh Tao and Koh Phangan, reached by boat on a full-day trip. Its walls fall from the surface to about 40 m, and its best-known feature is the Chimney, a vertical swim-through that calls for confident buoyancy control.
Big schools of chevron barracuda, trevally and batfish gather around the rock, and whale sharks are sometimes seen. Currents can be strong, so recent experience helps, and going below 18 m requires advanced or deep certification.
Location
Map & nearby sites.
Interactive map loads here. Every site on it is also listed on this page.
Right now · updated 12 Nov 2026
November is a good month to dive.
November scores 7.3, against 7.4 in its best months. Live sea readings from NOAA Coral Reef Watch and NOAA WaveWatch III as of 10 Nov 2026.
Water30 °C+1.2° vs normalTick: normal for Nov, 28 °C
Visibility18 mtypical for NovPoor days 15 m · 1 day in 4 is worse
Waves1.2 mModerate6 s period
Reef stressNo stressNOAA Coral Reef Watch heat stress
When to go
Best Apr-Oct.
Every month gets its own Divegrade score from that month's marine life, visibility, reef and reviews. Across Koh Tao as a whole, the best months are Mar-May.
Divegrade score by monthPick a month for its full guide
Water temperatureSurfaceDive depth28–31 °C
VisibilityBad day to great dayTypical10–36 m
How is this measured?
Mostly from years of satellite readings of how clear the water is around this site. Each bar runs from a bad day, which about 1 day in 10 is worse than, to a great day, which about 1 day in 10 beats; the line marks a typical day. Satellites can't see through cloud, so stormy days are underrepresented and the real bad days can be murkier. For 12 months here, local dive centers report worse days than the satellites see, so the bar starts at their figure. Logged dives will sharpen it over time.
Photos
8 photos. All from this site.
Divers pick the cover photo. Open any photo and vote for it; the one with the most votes leads this page.
Diver reviews
What divers who went say.
10.0
Exceptionalout of 10 · 1 review
9–10100%
7–80%
5–60%
3–40%
1–20%
Verified dives count more.
Reviews linked to a logged dive, and reviews from experienced divers, carry more weight in the score.
- 2.5×
- a review backed by a logged dive here, vs. one that isn't
- 2×
- a review from a 100-dive diver, vs. a first-timer's
Dived Sail Rock?Sign up free to share how it went. Import your dive log and your review counts as verified.Share how it went. Divers with a logged dive here get the verified badge.
Dive centers
Ten dive centers run Sail Rock.
Confirmed: each lists this site on its own website. Listed alphabetically.
| DIVE CENTER | AGENCIES | NITROX | CONTACT | Action |
|---|---|---|---|---|
Big Blue DivingKoh Tao | SSI | Not known | Website+66 77 456 123 | View |
Crystal DiveKoh Tao | SSI | Yes | Website | View |
Flow DiversKoh Tao | PADI | Yes | Website+66 82 679 2382OSMinfo@flowdivers.comOSM | View |
French Kiss Divers - ChalokKoh Tao | SSI | Yes | Website+66641276082frenchkissdivers@gmail.com | View |
Goodtime AdventuresKoh Tao | SSI | Yes | Website+66872753604OSM | View |
Hydronauts Diving ResortKoh Tao | RAID | Not known | Website+ 66 080 065 8782OSMinfo@hydronautsdiving.comOSM | View |
Nava Scuba DivingKoh Tao | PADI | Yes | Website+66 77 601198OSMinfo@navascuba.comOSM | View |
New Heaven Dive SchoolKoh Tao | SSI | Not known | Website+66 77 457 045info@newheavendiveschool.com | View |
Siam Scuba Dive CenterKoh Tao | BSAC, CMAS, NAUI, PADI, RAID, SSI | Not known | Websitesiamscubadivep@gmail.comOSM | View |
The Dearly Dive Koh TaoKoh Tao | PADI, RAID, SSI | Not known | Website+66-(0)77-332-494info@thedearlykohtaohostel.com | View |
OSM From OpenStreetMap (© OpenStreetMap contributors, ODbL), not from the center's own website.
Safety & rules
Know before you drop.
Depth, current and certification are safety calls. This isn't a dive briefing: your guide gives that on the boat or at the entry.
Hazards
No specific hazards recorded. That doesn't mean there are none: ask locally.
Rules and requirements
- Who can dive it
- Open Water Diver (or equivalent), typically to 18 m. Koh Tao sites for Open Water divers
- Local rules
- No specific rules recorded.
- Park fee
- None known
- Depth limits
- The site goes past 30 m, the usual recreational limit. Plan your depth with your guide and set your computer's ppO₂ alarm if you dive nitrox.
- Sources
- Dive center websites, derived, geonames, NOAA Coral Reef Watch and NOAA WaveWatch III.
If a diver is hurt: oxygen first, then call for helpFor suspected decompression sickness give 100% oxygen right away and contact local emergency services. DAN emergency hotline: +1 919 684 9111. Check where the nearest recompression chamber is before you travel, and carry dive insurance with evacuation cover.
Questions
When is the best time to dive Sail Rock?
April, May, June, July, August, September, October score highest for Sail Rock.
What certification do you need for Sail Rock?
Open Water. Open Water Diver (or equivalent), typically to 18 m. Depth 0-40 m.
How we grade
One number, built from dives people actually logged.
- Big draws or varietyMarine life scores the better of two things: how often sharks, rays, turtles and other big draws turn up, and how varied the reef life is, plus a little for having both. Both are per dive, so busy sites can't win on volume.
- By monthEvery month has its own score. Pick a month to see yours.
- Thin data, cautious scoreFew dives or reviews? The score leans toward the regional average.
- Graded as a pinnacleSail Rock is a deep, exposed offshore site, dived for the structure and the life it draws more than for coral. Marine life counts for 45% of the score here and the reef 10%.
- Reef healthThe reef score counts coral variety, and recent marine heatwaves that bleach coral take up to 3 points off it, fading over the years after as the reef recovers. Here: the 2024 marine heatwave (peak 8 °C-weeks of heat stress, when coral bleaching is likely), −0.8.
- Hard isn't worseCurrent and depth are shown on their own. A tough site can still score 10.
Sources for this page
Site facts: Dive center websites, derived, geonames, NOAA Coral Reef Watch and NOAA WaveWatch III. Occurrence data from GBIF.org; sea conditions from NOAA Coral Reef Watch and Copernicus Marine. Score computed 12 Nov 2026 from 0 logged dives and 1 review: low confidence.
Water temperature: average surface temperature by month from NOAA OISST climatology; at a typical dive depth here from the E.U. Copernicus Marine Service ocean reanalysis. Visibility: NASA satellite water-clarity data, local dive center reports and logged dives.
Photo credits
Longfin Bannerfish near Sail Rock: (c) portioid, some rights reserved (CC BY), via iNaturalist (CC BY). Leopard Coralgrouper near Sail Rock: (c) portioid, some rights reserved (CC BY), via iNaturalist (CC BY). Coral Grouper near Sail Rock: (c) portioid, some rights reserved (CC BY), via iNaturalist (CC BY). Giant Queenfish near Sail Rock: (c) portioid, some rights reserved (CC BY), via iNaturalist (CC BY).