Bikini Atoll

Nothing about this is casual. Diving is by liveaboard on a long charter, and the day is built around one or two dives with serious decompression rather than a rotation of tanks. Descents run down a shot line, teams stay together with an agreed plan for the part of the ship they intend to see, and ascents typically finish hanging on a bar with gas staged for the stops. Between dives there is very little to do and nowhere to go, which is a real part of what the trip feels like.

Scale is what catches people out. These are capital ships, and the water never shows you a whole hull, so a single dive covers a deck, a turret or a stretch of hangar and nothing more. Several are capsized or resting on their superstructure, so orientation has to be worked out in the water rather than assumed from a plan; the carrier settled upright hours after the underwater shot, while one battleship stayed afloat for days before going down inverted. Growth is light for the depth and the years, and the steel still reads as machinery.

The draw is swimming through recent history that was destroyed deliberately and in public: guns still trained where the crews left them before the ships were abandoned as targets, ladders and hatches and fittings intact, an operation filmed and photographed from every angle at the time. Read the rest of it first. The atoll's people were moved off in 1946, a resettlement in the 1970s was reversed after radiological testing, and the islands stay uninhabited apart from an intermittent caretaker presence, so boats provision entirely from outside.

It suits experienced deep divers comfortable with staged decompression, long hangs, a rigid plan and being a very long way from a chamber. Charters run the calmer April-to-November months and have started and stopped over the years as operators and permissions change, so confirm a trip is genuinely sailing before booking flights across the Pacific. Radiation questions come up constantly; the standing view is that a short visit spent mostly in the water is low exposure, with locally grown food the concern rather than the lagoon.