Lundy Island

Getting there is part of the dive. Boats cross open water from the north Devon coast, which makes this a full-day commitment and stakes the whole trip on one forecast: when it blows out there is nothing to move round the corner to, unlike a mainland coastal site. Once on station the skipper works whichever side of the island is sheltered and puts divers in during short slack windows, so the day is two dives placed precisely rather than whenever people happen to be ready.

Underwater the island is what it looks like from the boat: granite, split into gullies, boulder runs and steep faces, with kelp over the shallow shelf thinning below it to bare rock and patches of sand. The east side is sheltered, shallower and forgiving; the west takes Atlantic swell and only opens up in settled weather. Off the north and south ends the tidal streams are strong enough that they, rather than depth, decide where anyone gets in at all.

The seal diving runs against most people's instincts. Chasing ends the encounter; staying shallow, staying still and keeping your hands to yourself extends it, so the productive dive is usually a long, unambitious one over kelp and sand in decent light. Let them come from behind and expect to be inspected for as long as you stay interesting. The boats take the island's protected status seriously — the no-take zone on the sheltered east side has been in place since 2003 — and briefings say so.

It is an intermediate destination rather than a hard one: modest depths, straightforward diving, and a skipper doing most of the difficult thinking. What has to be right is punctuality, because a team late into the water gets an unplanned drift instead of the dive it booked. Wreck divers should temper expectations, since what lies here is mostly broken and scattered and the diving is really about rock and animals. Divers happy to spend an hour photographing one seal over a kelp bed, with granite and shallow light around it, get exactly what they came for.