Galápagos — Darwin & Wolf

Darwin and Wolf cannot be booked on their own. The licensed vessels run fixed itineraries — usually a week — that give three or four days to the two northern islands and spend the rest on the central and western archipelago, so the pair arrive attached to a whole trip rather than as a day's diving. The run up from the central islands is an overnight crossing in open water and the return leg is the same, which puts the northern days in the middle of the week rather than at either end.

Once there, the pattern repeats: three or four dives a day off the pangas, all of them at the same two islands. Entries are negative and quick, because the surface current can carry a group past the site in the time it takes to clear your ears. The dive itself is mostly stationary — you settle onto a rocky ledge out of the worst of the flow, stay low and watch the wall and the water above it. Neither island can be landed on, so between dives the ship sits in the lee and the day is water, deck, water.

The rest of the itinerary is what stops the trip being a queue for sharks. Cold upwelling along the west sides of Isabela and Fernandina produces completely different diving: dark volcanic rock, cool green water, marine iguanas grazing in the shallows, and the sunfish and rays that give the archipelago its odd, un-tropical character. A sheltered central site near Santa Cruz usually covers the check-out dive, and the last day is normally kept dry before the flight home.

Conditions do the filtering. Visibility here runs well short of tropical numbers, surge works the shallows, and current at the northern sites can change direction partway through a dive. A hood and a thick suit are normal kit on the equator. It suits divers who already handle moving water without thinking about it, and who want a trip where the topside — sea lions on the swim step, the seabird colonies, the islands themselves — counts for as much as the dives.