Perpendicular Wall

The boat runs in tight to the island and drops you under an overhang, so the dive starts against the rock rather than out in open water. The face then falls away vertically and keeps going past anything you can see, so there is no sand or slope to level off on and no terrain to set your depth for you. You pick a level and follow it, rock on one shoulder and open water on the other, reading the gauge instead of the bottom.

The face itself carries huge fan corals with moray eels in the cracks, and batfish come in close while pelagic fish pass by out in the blue. This is one of the sites where the island's big animals turn up: the operator lists sharks, sailfish and whale sharks among the big fish on this wall, so it pays to look off the face into open water as often as at the rock.

How deep you go is left to the diver here, with the operator's own guidance being to treat 30 m as the maximum and work the wall above it. That makes the shape of the dive the usual one for a bottomless face: take the deepest point early, let the profile step up as the dive runs on, and finish shallow along the top of the wall, where the stop can be made against the rock instead of hanging in open water. Current can run strong along the face, so the ascent is planned before you drop in.