Escape the beach and explore the sea by kayak. Rent one in the southwestern town of Guanica and spend the day island-hopping. Gilligan’s Island—accessible by kayak or by ferry—is a popular destination, with lots of picnic areas and places to dive into the water from the trees. Whale Island is only accessible by kayak, and draws visitors with the promise of whale sightings from December to March—and with the prospect of not sighting a single other person. Make sure to take the time to snorkel—all kinds of fish, coral, seashells, starfish, barracudas, crabs, and anemones can be found just below the water’s surface.