Koh Lanta & Hin Daeng: Thailand's Pelagic Frontier
Far south of Phuket, two isolated pinnacles rise from the deep Andaman Sea — and bring with them mantas, whale sharks and the strongest soft coral colours in the country.
Hin Daeng and Hin Muang sit alone in 60 m of open water — the closest reef to Sumatra in the Thai EEZ. They consistently rank among Asia's top ten dive sites for one reason: the sheer odds of a serious pelagic encounter.
The two pinnacles
Hin Daeng (Red Rock) breaks the surface and is fringed by spectacular crimson and purple soft coral. Hin Muang (Purple Rock) sits entirely submerged 200 m away — its plateau begins at 8 m and the wall plunges past 70 m.
Both are exposed to current, which is exactly why the pelagics come.
Mantas and whale sharks
Between February and May, both manta rays and whale sharks visit the pinnacles to feed on plankton concentrated by the current. Sightings are never guaranteed, but the strike rate during peak season is among the highest in Thailand.
Getting there
Most divers base themselves on Koh Lanta or Koh Phi Phi for day trips (1.5–2 h boat ride), or join a southern Andaman liveaboard out of Phuket combining Hin Daeng, Koh Haa and the Mergui Archipelago.
Ready to dive Thailand?
Let our experts design a custom itinerary tailored to your level and bucket list.
Create my dive tripFrequently asked questions
What level is required?+
Advanced Open Water minimum, plus comfort with current. Nitrox is highly recommended.
When is the best season?+
February to early May — best visibility, plankton blooms and manta/whale shark activity.
