Cabo Douglas

Cabo Douglas, on Fernandina's black lava coast, exists on itineraries for one reason: it is the place to dive with feeding marine iguanas. In the late morning, when the reptiles have warmed enough to work, they swim down through the surge and clamp onto the rock, tearing at algae with sideways bites while exhaled salt streams behind them. Nothing else in diving looks remotely like it. Flightless cormorants rocket past chasing fish, sea lions patrol the edge of the action, and turtles graze the same pastures. It is a shallow, cold, surgy dive of modest technical interest and outsized wonder - the Galapagos distilled to a single scene.

The moment you come for: Marine iguanas grazing underwater, flightless cormorants hunting, sea lions in the surge

Topography: Lava rock and algae-covered boulders in the shallows

Current: Shallow and surgy rather than swept; timing follows the iguanas' feeding schedule, not the tide alone.

Hazards: Cold water, surge against lava rock, shallow working depths near shore.

Conservation: Fernandina is among the most pristine islands on earth; park rules on distance and no contact are enforced absolutely.