Djibouti — Gulf of Tadjoura

Diving runs from small boats out of the city, and in the whale shark months the day is organised around finding the animals rather than around a dive plan. The boat works the shoreline of the bay looking for a fin, drops people ahead of a shark, picks them up and repeats until everyone has had enough. Encounters are normally run on a breath-hold, since the sharks feed at the surface and bubbles tend to push them down; scuba fits around that, usually a reef dive on the way out or back.

The Gulf of Tadjoura is a flooded arm of the rift system that splits the Afar, and the geology reads volcanic rather than tropical: lava shoreline, dark sand, steep-sided inlets and coral growing on old flows instead of a broad reef shelf. At the western end the water narrows into a near-landlocked inner basin joined to the gulf by a strait that runs hard with the tide. The island reefs off the city are the opposite, shallow and sheltered and under an hour out, and they carry the everyday diving.

The far offshore islets are a separate trip rather than an extension of the day: they lie well to the north toward the strait, and reaching them normally means an overnight or multi-day charter and a settled forecast. Expect a small industry throughout, where boat and guide availability rather than the length of the site list shapes the week. Photographers should arrive set up for close, wide work in green water, because the bloom that feeds the sharks is also what you are shooting through, and the animals are juveniles of a few metres rather than full-grown adults.