Barracuda Point is the signature dive and the reason most people come: a current-swept corner where chevron barracuda mass in a slowly rotating tornado of thousands of fish, with grey reef and whitetip sharks patrolling beneath and bumphead parrotfish grazing the top.

The Drop Off, directly off the old jetty, is the wall in its purest form — a vertical face from the shallows into blue, and the easiest place in the world to swim with green and hawksbill turtles, which are so abundant here that divers stop photographing them by the second dive.

Turtle Cavern is a limestone cave system holding the skeletons of turtles that entered and could not find the way out. It is a sobering site, and penetration beyond the entrance is restricted to properly trained divers.

Mabul and Kapalai, the shallow reefs where you actually stay, are world-class muck diving in their own right — flamboyant cuttlefish, frogfish, blue-ringed octopus and mandarinfish — and you will dive them far more often than Sipadan itself.

The permit system

Nobody lives or stays on Sipadan; accommodation was removed from the island, and you stay on Mabul, Kapalai or in Semporna. Sabah Parks issues a capped number of daily permits covering divers and snorkellers, allocated to licensed operators rather than to individuals — you cannot buy one yourself, and you cannot turn up and dive.

Operators receive a small daily allocation and distribute it by rotation, which rewards longer stays: three nights is usually the minimum for a permit at all, and four or five materially improves your chances of more than one Sipadan day. Advanced Open Water certification or equivalent is required. The island closes to diving for the whole of November each year. Book many months ahead and treat any operator guaranteeing same-week permits with suspicion.