A five-minute boat ride from town is this wonderful snorkeling spot, a small volcanic island with marine iguanas, penguins, boobies and other birdlife, rays, marine turtles and the occasional white-tipped reef shark. It’s especially fun to swim through the narrow fissures in the rocks, which are like underwater hallways decorated with plant and coral life. Tour operators charge $40 for the 2½-hour outing.