Hin Wong Pinnacle Dive Site, Koh Tao: Depth & Current

Hin Wong Pinnacle is the east coast's headline dive and one of the best Advanced dives around Koh Tao. It is a chain of large granite boulders about 1.5 km off Hin Wong Bay, reached from Hin Wong Pier by shuttle boat and dive boat in roughly 15 to 20 minutes. The shallowest rock, a flat-topped table at the south end, comes up to about 8 m, and the rest of the site drops through tiers to 30 m and beyond.

What sets it apart is the cover on the rock. Purple soft tree corals, sea whips, gorgonian fans, sponges and anemones plaster the granite, and the current brings in barracuda, trevally and the odd whale shark. It is not a gentle dive, but it is a rewarding one for confident divers who are comfortable with depth.

Hin Wong Pinnacle dive site map

1South tabletop rock, top 8 m
2Central boulder stack, 12 to 30 m
3North boulders, 12 to 28 m
4Long trench, 18 to 28 m
5Purple soft corals, east face
6Sand at base ~32 m

Usual route: Descend on the south tabletop, work north along the boulder chain through the trench and swim-throughs, then ascend gradually and finish with a safety stop on the tabletop or in the blue. Drawing based on local dive briefings: approximate, not to scale and not for navigation. Your guide's briefing on the day always comes first.

Diving Hin Wong Pinnacle: the route

The classic plan is to descend on the south tabletop, then work north along the boulder chain. Use the long trench and the swim-throughs as you go, and keep the corals on the east face in view. Most dives stay at 18 to 28 m.

Ascend gradually up the rock and finish with a safety stop on the tabletop or in the blue. A delayed surface marker is worth carrying because of the current.

Because the structure is a long chain, you can follow it either way and simply move up or down the rock to manage your depth. That flexibility is one of the nice things about the site. If you are on Nitrox, the 18 to 28 m band where most dives happen gives you good bottom time.

The pinnacle is often paired with Hin Wong Bay, Lighthouse Bay, Laem Thian or Shark Island, so a second dive in shallower water is easy to arrange. The Pinnacle trip also tends to feel much quieter than the busier west-coast sites.

Underwater layout

The site is a north-south line of large granite pinnacles. The table rock at the south end is the shallowest point at roughly 8 m, while other tops sit around 10 to 12 m. From there the rock steps down in tiers through boulder stacks to sand at around 30 m. Maximum depth is quoted up to 40 m, although exact depths vary with the tide and where you measure.

A long trench runs through the formation, with swim-throughs and small caves between the boulders. Head east after your descent to find the purple soft tree corals, while sea whips and gorgonian fans cover the walls throughout. Triggerfish patrol the sand patches around the base, especially when nesting.

Marine life at Hin Wong Pinnacle

The current is what makes this site busy. Trevally, queenfish and barracuda hunt bait balls around the rock, and large brown marbled groupers hide inside the boulders. Hawksbill turtles are resident.

Common: fusiliers, bannerfish and butterflyfish, trevally and queenfish, harlequin sweetlips, titan triggerfish, brown marbled grouper, striped squirrelfish and scribbled filefish.
Now and then: whale sharks, cobia, rainbow runners, giant morays, banded sea snakes and cuttlefish.
Macro: nudibranchs, scorpionfish, white-eyed morays and razorfish.

Conditions and best time to dive

Current is mild to moderate and occasionally strong, and this site is more exposed than most on the west coast. Visibility can be anywhere from 2 to 25 m, and most often 10 to 20 m when conditions line up. A thermocline can appear, so a thin extra layer is not a bad idea.

June to September is best, when the south-west monsoon shelters the east side. October to December, under the north-east monsoon, is the season to avoid. When the west side is rough, this is a worthwhile alternative.

It pays to be honest about this site: conditions are changeable. One day the water is blue and clear and the fish are packed in, the next you are in a thermocline with limited visibility. Your guide will read the conditions at the surface, so trust the briefing.

Tips from local divers

Use a nitrox mix if you are certified, the depths sit right in the useful range.
Head east after the drop to find the purple soft corals.
Carry a delayed surface marker buoy because of the current.
Bring a light for the crevices and swim-throughs.
Check the day's visibility, it can swing from poor to excellent.

Safety notes

This is an Advanced-level site. The typical depth, the current and the changeable conditions all add up, and it is often used for Advanced Open Water deep dives, Deep Diver specialty courses and nitrox. Depths go beyond 30 m, so plan your gas and no-stop time carefully, and avoid the site in the north-east monsoon.