Dhonfan Thila

The point of the oval pinnacle faces the prevailing current, which splits and runs down both flanks. Divers usually drop in up-current of the point and descend to around 22 metres to meet it, then work along a current-swept outside and a calmer lee. Grey reef sharks hold along the outer edges, and a pelagic circle of eagle rays, big-eyed jacks and barracuda moves round the pinnacle.

The reef top, 7 to 8 metres down, carries schools of fusiliers, snappers and anthias, with batfish, octopus and lionfish among the coral. The slope down to about 18 metres is the part an Open Water diver keeps to. Below that sit the canyon on the side opposite the swim-through, falling to 25 metres, and overhangs at 27 metres on the east side and 20 metres on the north, where sea turtles rest.

The swim-through is the Advanced part of the dive. It is quite narrow, its lower end is variously put at 25 or 30 metres, and its upper opening lies near 18 metres. The water goes noticeably calmer once you are inside.

Reef mantas feed on top of Dhonfanu Thila, at a depth any Open Water diver reaches. Sightings vary from dive to dive.

One oval holds two dives: grey reef sharks patrol the outer edge, and a swim-through, a canyon and overhangs shelter the structure beneath. Inside, the water stays still when the outside is running. Napoleon wrasse approach divers along the structure.

Current changes around the pinnacle. It runs moderate on the exposed outer edges and eases inside the pinnacle, so settle the drop-in with your guide and carry a surface marker buoy for the finish.

Take the swim-through slowly. The passage is narrow, with black coral bushes along it: plan your gas and no-decompression time before you commit to it, and hold your trim so the coral stays untouched.