Hin Bai (Sail Rock area)
Sail Rock · Hin Bai · Koh Sail
9°51.3'N 100°0.0'E
Depth
10–30m
Bottom
sand
Alarm Radius
100m
Holding
Poor
Recommended Anchor Alarm Radius
100m
Set 100m radius minimum — this is an open-ocean dive site pinnacle with no shelter. Anchoring here is only practical in calm conditions. Mooring buoys installed by dive operators should be used in preference to anchoring. Suitable only as a day stop in good weather.
About This Anchorage
Hin Bai (Sail Rock) is a spectacular underwater pinnacle rising from 40m to the surface between Koh Phangan and Koh Tao, widely regarded as one of the Gulf of Thailand's best dive sites. The pinnacle breaks the surface with a distinctive triangular rock formation. A chimney through the rock allows spectacular through-dives. Grouper, barracuda, and occasional whale sharks are sighted here. This is a day-stop dive site only — not a practical overnight anchorage. Permanent mooring buoys installed by dive operators.
Protected From
variable
Exposed To
all directions (open ocean)
Anchoring Rules
- Anchoring fee
- Free (mooring buoys available — use buoys in preference to anchoring)
- Maximum stay
- 1 days
- Permit required
- No
Restrictions: Use mooring buoys when available. Do not anchor on the pinnacle or adjacent reef. Suitable as a day stop only — not an overnight anchorage in any normal weather conditions. If remaining overnight, set anchor alarm to maximum sensitivity.
Hazards
- !Open ocean site — no shelter in any direction; only practical in calm settled weather
- !Strong currents around the pinnacle — variable direction, up to 2kt
- !Dive boat traffic throughout the day — watch for dive flags and SMBs on approach
- !Swell from any direction in open-ocean location
Skipper's Tips
- →Use the permanent mooring buoys installed by dive operators when available
- →Visit only in the calmest weather — December–May window when Gulf is at its calmest
- →Book a dive with a Koh Tao operator — they will guide you to the best dive conditions
- →Whale sharks sighted regularly April–May and October–November
Facilities
Nearest provisions: Mae Hat village (Koh Tao) (15nm)
Best Months & Season
March, April, May, June, July, August, September, October
Day-stop only in good weather. Best visibility April–May and October–November. Not suitable as an overnight anchorage for most vessels.
Recommended Anchor Types
Nearby Anchorages
Set Your Anchor Alarm to 100m
In the Gulf of Thailand, unexpected NE squalls can develop overnight and ferry wash can drag an unmonitored anchor. Safety Anchor Alarm monitors your GPS position continuously — so you can enjoy the Full Moon Party, dive sites, and tropical evenings knowing your boat is protected.
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