Off the southwest coast, near Guánica, is Gilligan's Island, a palm-ringed cay skirted by gorgeous beaches. You'll find picnic tables and restrooms but few other signs of civilization on this tiny island, officially part of the Bosque Estatal de Guánica. Wooden boats line up at the small dock in the San Jacinto section of Guánica, off Route 333 just past the Copamarina Beach Resort. Boats depart every hour from 9 to 5. Round-trip passage is $8. The island is often crowded on weekends and around holidays, but during the week you can find a spot to yourself. Nearby Isla de Ballena, reached by the same ferry, is much less crowded. Amenities: toilets. Best for: swimming; solitude (mid-week, low season only).
Off Rte. 333, Guánica, 00653, Puerto Rico