Palomino Islands

Trips run as half-days out of Callao, and the dive boat is often the same one carrying snorkellers and sightseers, so expect a mixed load and a schedule built around the group. The crossing goes through working harbour water — Callao is Peru's main commercial port — and past the bulk of San Lorenzo before the outer rocks come into view. There is no beach and nowhere to stand, so the whole dive happens off the boat, and being settled in the first few metres counts for more than any depth experience.

What you dive are the flanks of the islands: steep rock faces and jumbled boulder slopes crusted with mussels, barnacles and encrusting invertebrates, with fish holding tight to the stone rather than hanging in open water. The Humboldt Current sets the terms — cold, nutrient-heavy upwelling that keeps the water dark and the biomass high, so the murk and the life come from the same source. Current picks up around the exposed corners of the islands.

The sea lions set the pace. Groups come off the rocks soon after the boat settles, and the encounter plays out in the top few metres, where there is still light and the animals are willing to stay with you. Below that it becomes a slow, close-range dive worked on a torch, along cracks and ledges rather than across ground, and cold rather than depth is usually what ends it. It suits divers based in Lima who want a real dive morning inside the city's reach, and anyone happy to trade visibility for animals.