Hin Daeng (Red Rock)

Hin Daeng — “Red Rock” — earns its name from the vivid red and purple soft corals that encrust every surface of this dramatic underwater pinnacle. Rising from over 60 metres depth to within 6 metres of the surface, it’s one of the Andaman Sea’s most spectacular dive sites, and almost certainly Thailand’s best for manta ray encounters.

Manta Rays

From January through April, oceanic and reef manta rays aggregate at Hin Daeng in extraordinary numbers. The current-swept tip of the pinnacle creates an upwelling that concentrates the plankton these enormous, graceful creatures feed on. On a good day, you might count 10, 15, even 20 manta rays in a single dive — their 3–5 metre wingspan making them look, from below, like black kites flying across the blue.

No diving experience is quite like a manta ray aggregation at Hin Daeng. The sight of multiple mantas looping in feeding spirals while barracuda schools circle and the current sweeps past the coral wall is one of the most thrilling spectacles in the underwater world.

The Wall

Below the manta action, the wall plunges steeply to 40m and beyond, its surface covered in some of the most prolific soft coral growth in Thai waters. The reds and purples of the coral, brilliant in torch light, contrast with the deep blue of the open water — visual drama to match the marine life.

Whale Sharks

Between February and April, whale sharks pass through Hin Daeng regularly — often appearing during the same dives as manta rays for an almost unfair level of big-animal action.

Getting There

Hin Daeng is accessible by day trip from Koh Lanta (45 min) or by liveaboard from Phuket. The exposed location means the site is weather-dependent — it’s best dived in calm conditions, which are most reliably found from January to April.