San Cristóbal has a different tempo from Santa Cruz. The wildlife here is just as extraordinary, but you share it with fewer tourists — most cruise itineraries skip San Cristóbal or stop only briefly, which leaves the island's trails and snorkel sites uncrowded by Galápagos standards. The Darwin connection is genuine: this was the first island he stepped ashore on in 1835, and the Interpretation Centre does a remarkable job of explaining what he found and what has happened since. Most of the island's best sites require a half-day or full-day boat tour, which you can arrange through agencies on the main street.
The wildlife encounters here are as close-up as anywhere in the archipelago. Sea lions occupy the waterfront benches with the authority of long-term tenants. Frigate birds nest within walking distance of town. Kicker Rock offshore is a world-class dive and snorkel site. And Punta Pitt, at the island's northeastern tip, offers something you cannot see anywhere else on earth: all three booby species nesting side by side in a single colony. Come prepared for both sun and wind — San Cristóbal's south-facing coast and highland interior are wetter and cloudier than the other main islands, which is part of what makes it so green.