Hin Muang Pinnacle

Nothing marks Hin Muang at the surface. The rock lies 500 metres from Hin Daeng and stays submerged, so the dive begins with a descent onto a wall rather than onto anything you can see from the boat. What you find is described as Thailand's highest vertical wall, covered in purple soft corals — the feature that gives the site its Thai name — with one side of the submerged rock levelling out at around 60 metres and the other disappearing into the abyss.

Recreational profiles stay in the 25 to 40 metre band, running the wall with rock on one side and open water on the other. Current is medium to strong, and Hin Muang in particular is more challenging in current than Hin Daeng, which puts the site in experienced-diver territory; the leeward flank of the boulder wall is where the group shelters. Sea fans cling to the steep faces, and grey reef sharks and leopard sharks are often seen patrolling the depths below.

Hin Muang is the larger of the two rocks, and because so much of it lies deeper than most Thai diving reaches, it tends to be less crowded than its neighbour. Manta rays are seen here as they are at Hin Daeng. Visibility is rated at 30 metres and better and the water runs 27 to 30°C. The site sits inside Thailand's Mu Koh Lanta National Marine Park.