Guadeloupe — Cousteau Reserve

Diving here runs on short crossings. Boats leave the beach at Malendure on Basse-Terre's west coast and are over the Pigeon islets within minutes, so centres tend to schedule several departures through the day rather than committing everyone to one long morning, and adding a dive at short notice is usually straightforward. Briefings are given in French, with English available at most shops if you ask for it. It is busy water: snorkel boats, glass-bottom boats and dive boats all work the same sheltered channel.

Basse-Terre is a volcanic island and the ground underwater shows it. Basalt boulders and lava slabs stack into ledges and swim-throughs, with coral, sponge and sea fans growing over the rock rather than building a continuous reef, and dark volcanic sand shelving away beyond. The islets sit inside protected water managed as part of the national park, so boats pick up moorings instead of anchoring. Sites separate by exposure more than by depth: the channel stays flat on almost any day, while the island tips pick up moving water and hold more fish.

Because the profiles are gentle, most of the interest is close-range work — octopus in the rubble, nudibranchs on the sponges, turtles grazing while snorkellers cross overhead — and night dives on the same shallow ground are a fixture rather than an event. The offshore seamount is the deliberate opposite: a long open crossing, no shelter and real current, with a summit inside recreational range and flanks that fall straight past it. It runs only when the sea is flat and enough divers sign on, so plan for it but expect it to move.

That mix suits new divers, families splitting their time between diving and snorkelling, and photographers who would rather work a small area repeatedly than cover distance. Mixed-ability groups do well, since one crossing can serve both an easy coral dive and a livelier point. Divers who want big animals on every dive, or a lot of variety, will work through the core sites in a few days; the honest approach is to treat the reserve as one part of a wider Guadeloupe trip.