Cocos (Keeling) Islands

Diving here runs off the tide table rather than the clock. The islands support one small dive operation, working out of West Island with small boats and smaller groups, and the day's plan comes from the state of the tide and from which side of the atoll the trade wind is pushing. A two-dive morning is the usual shape, with the surface interval spent ashore on a beach or a sandbar. Nothing about it is high volume, and you are unlikely to share a site with another boat.

The atoll offers three quite different kinds of dive. Inside the lagoon the water is shallow and sheltered, coral heads standing on clean sand, which makes an easy first day or a gentle afternoon. The passes cut through the rim, and that is where the water moves — you drop in, get carried, and tuck in behind the reef edge to watch what is holding station in the flow. Outside the rim the ground falls away into open ocean, and those outer profiles are where animals appear out of the blue with no warning.

The Rip is a one-way ride off Direction Island. The boat sets you in at the top and pickup happens wherever you surface, which is why it runs on the outgoing tide and why the rest of the day gets planned around it. Snorkellers can be dropped on the same water on the same tide, so non-divers in a group are not left ashore. It is short enough that repeating it across consecutive days makes more sense than treating it as a one-off.

It suits divers content with a modest number of sites dived properly rather than a long site list. There is no recompression chamber on the islands and any evacuation is a long flight away, so conservative profiles and dive insurance matter more than usual. Fish watchers get a second reason to come: Cocos sits on the seam where Indian and Pacific reef fish ranges meet, and the resulting hybrids among butterflyfish, angelfish and surgeonfish are well documented here and at Christmas Island.