Bazaruto Archipelago

Diving here is a logistics exercise. The reefs lie out between the islands, so a day starts with a long boat ride, much longer from the mainland than from an island lodge, and it is planned around the tide, because the exchange between the bay and the open sea is what makes or ruins a dive. Two dives fills a morning. Crews watch the swell as closely as the clock, and having the reef you were promised swapped for a more sheltered one is a normal part of the week.

There is no fringing reef to swim out to. The islands themselves are sand, high dunes and freshwater lakes with almost no exposed rock, and the coral grows instead on submerged ridges offshore, cut by sand gullies that run roughly with the flow. Sites differ mostly by exposure: the inner ground is broader and calmer and takes most of the traffic, while the outer ridges sit further into the current and are where the bigger animals cross. Inside the bay it is seagrass and sand.

The draw is the chance of something large in open water, over coral that is in reasonable condition but is not really why people come. Mantas holding on a cleaning station and kingfish working the ends of a ridge both come down to being in the right spot while the water is moving, which is why crews chase the tide rather than the site list. Conditions shift fast enough that two divers describing the same reef a week apart can sound as though they were nowhere near each other; the settled middle of the year is the safer bet.

It suits divers who take a trip as a series of chances rather than a guarantee, and who are content with a couple of dives a day from a remote base with little else running. The park's rules are enforced, lodges are effectively the only infrastructure, and costs sit at the top end of the Mozambican coast as a result. What decides whether someone enjoys it is less the card in their pocket than their tolerance for moving water and hours on a boat, so anyone prone to seasickness should think hard about the crossings.