The primary draw of the Corn Islands is underwater. The reefs here are among the healthiest in the Caribbean — partly because the islands are remote enough to have avoided the worst of the regional overfishing and tourist pressure. Dive sites ring both islands, and Little Corn in particular has become one of the most affordable places in the Caribbean to get certified. Blowing Rock, a volcanic pinnacle about 11 kilometres from Big Corn, is considered one of Nicaragua's best dive sites: it draws nurse sharks, eagle rays, and large schools of fish.
For non-divers, the snorkelling is also exceptional. Reef systems come close to shore on Little Corn, and guided snorkel trips typically cost USD $25–40 per person. You can see turtles, rays, and reef fish without ever putting on a tank.
Above water, the islands reward slow exploration. On Big Corn, the road around the island takes you past fishing communities, mangroves, and lookout points. On Little Corn, the only way around is on foot — a walk across the island through jungle paths takes about twenty minutes and gives you a real sense of the place.