I thought Puerto Rico was an island -- but how can an island have an island? Well, Puerto Rico has two, Vieques and Culebra, for years a well-kept secret among Puerto Ricans themselves, who come here to escape the tourists on the big island. Since the U.S. Navy, in 2003, closed its installation on Vieques, though, much more land is available for vacationers, and Vieques is rapidly becoming known as an ecofriendly -- and still charmingly scruffy -- destination.
With some 40 palm-lined white-sand beaches, and reefs of snorkel-worthy antler coral off shore, Vieques -- 11km (6 3/4 miles) off the big island's east coast, only an hour by ferry -- has an obvious appeal for sun-loving families. But one of the coolest things on Vieques has nothing at all to do with the sun. Just west of the main town, Isabel Segunda, lies Mosquito Bay, which has been renamed Phosphorescent Bay for the way its waters glow in the dark, thanks to millions of tiny bioluminescent organisms called pyrodiniums (translation from science-speak: "whirling fire"). They're only about one-five-hundredth of an inch in size, but when these tiny swimming creatures are disturbed (by, for example, a hovering tour boat), they dart away and light up like fireflies, leaving eerie blue-white trails of phosphorescence. These pyrodiniums exist elsewhere, but not in such amazing concentrations: A gallon of water in Mosquito Bay may contain upward of three-quarters of a million such creatures. It's definitely worth letting the kids stay up late for once. Wear a bathing suit because it's possible to swim in these glowing waters. Don't make the mistake of coming here on a full moon, however -- the glow of the pyrodiniums is only discernible on a cloudy, moonless night. (Warning: Some tour boats go out to the bay regardless of the full moon -- and you won't get your money back if you're disappointed.)
Island Adventures (tel. 787/741-0720; www.biobay.com) operates 2-hour nighttime trips in Phosphorescent Bay aboard the Luminosa, though not during the full moon. If the kids are into kayaking, they can get even closer to those glow-in-the-dark waters on a kayak tour offered by Blue Caribe Kayaks (tel. 787/741-2522; www.bluecaribekayaks.com). In fact, Blue Caribe acts as a clearinghouse for all the island's watersports outfitters -- it's a small island, and virtually everybody is related to everyone else. That small-town casualness is one of the things that still makes Vieques a great place for traveling families, hot spot or not.
Where to Stay: $$ The Crow's Nest, Rte. 201, Barrio Florida (tel. 877/CROWS-NEST [276-9763] or 787/741-0033; www.crowsnestvieques.com). $$ Trade Winds Guest House, Calle Flamboyan 107, Esperanza (tel. 787/741-8666; www.tradewindsvieques.com).