Hin Ngam Dive Site, Koh Tao: Depth, Map & Marine Life

Hin Ngam means 'Beautiful Rock' in Thai, and the Hin Ngam dive site on Koh Tao lives up to it: granite boulders and coral-covered outcrops sit on a sandy bottom in a sheltered corner of the south-east coast. Maximum depth is only about 12 m, which means long bottom times and a relaxed pace.

Boats take roughly 15 to 20 minutes from the main pier, and the site is often paired with Shark Island, Aow Leuk or White Rock. Some guides treat the southern end of Aow Leuk bay as Hin Ngam too, so you may hear the name used for slightly different spots.

Hin Ngam dive site map

1Granite boulders, 3-10 m
2Rocky wall, 3-8 m
3Sandy bottom ~12 m
4Reef modules and nurseries

Usual route: Descend on the mooring, follow the boulders at 5 to 10 m, cross the modules on the sand, then return along the rocks for the safety stop. 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 Ngam: the route

You usually descend on the mooring, then work along the boulders and coral bommies at 5 to 10 m. The next stop is the artificial reef modules on the sand, before heading back along the rocks and finishing with a safety stop on the shallow reef.

Because everything sits within a small area, there is no need to rush. It is a good site for slow, close-up looking.

Why dive Hin Ngam on Koh Tao

It sits in a useful middle ground. It is deeper and more interesting than a bare training bay, yet gentle enough that nobody feels pushed. That mix makes it a favourite for Open Water training dives, refreshers, buoyancy practice and reef-conservation dives.

The shallow maximum also means plenty of time at depth. A single tank can easily stretch to a long, unhurried dive, with time to look into each ledge and crevice.

Underwater layout

A rocky shoreline gives way to sand dotted with coral bommies. The boulders and a rocky wall along the edge carry hard and soft corals, with ledges and crevices that hide small animals. Sandy gaps between the rocks are resting areas for rays.

Depth runs from a few metres at the rocks to about 12 m on the sand. Some operators quote deeper sections of 18 m or more, so exact depths vary with where you measure. The map is schematic and the positions of the modules are not confirmed.

Marine life at Hin Ngam

Reef fish: damselfish, wrasse, parrotfish, butterflyfish, fusiliers and clownfish in their anemones.
Bigger residents: schools of snapper circling the larger rocks, groupers and moray eels in the crevices.
On the sand: rays resting between the boulders.
Macro: nudibranchs, frogfish, scorpionfish, pipefish, yellow boxfish and mantis shrimp.
Occasional visitors: reef sharks, green turtles and eagle rays.

If you are a photographer, this is one of the better places on the south-east coast to spend a whole dive on a few square metres of reef. Frogfish, pipefish and mantis shrimp reward patience more than distance.

Coral restoration at Hin Ngam

Reef modules and coral nurseries have been placed here to rebuild damaged reef and give juvenile fish shelter. Algae and sponges settle on the new structures first, then coral follows. Exact dates and operators are not confirmed.

Do not confuse it with the Suan Olan project in neighbouring Aow Leuk, which is a separate artificial reef.

Conditions and best time to dive

Current is usually light in the sheltered bay, though the more exposed southern edge can see moderate flow. Visibility is typically 10 to 25 m, and divers report 18 to 30 m in some months.

The calm months of February to May are good, and so are June to September, when the east side is sheltered while the west coast gets windy. Late October to December, in the north-east monsoon, is the weakest time.

Check with your guide where the nursery frames are placed on the day, and plan your finning so you pass well above them.

Tips from local divers

Come when the west coast is rough. This side is sheltered.
Check under ledges for frogfish and scorpionfish.
Stay neutrally buoyant. The nurseries and new structures are fragile.
Bring a camera if you like macro, because you will have the time.

Safety notes

Scorpionfish and stonefish are well camouflaged, so keep your hands off rocks and coral. Boat traffic from nearby sites can pass overhead, so ascend near your buoy line.

Visibility can vary a lot from day to day on this coast, so listen to your briefing. If the bay is stirred up after rain, the boulders and wall near the shoreline are usually still worth a slow look, and the shallow depth keeps the dive comfortable either way.

Finally, remember that Hin Ngam is small. Two dives in a row here is a good way to see both the boulders and the sandy modules without feeling you have missed something.