5 Best Sights in Vieques and Culebra, Puerto Rico

Part of the Refugio Nacional de Vida Silvestre de Culebra, uninhabited Isla Culebrita is clearly visible from the northeast corner of Culebra. An essential day-trip excursion, this islet is a favorite destination for sunbathers, snorkelers, and boating enthusiasts. Isolation amid a palette of crystalline, turquoise waters, and dewy, lush greens makes for a one-of-a-kind natural experience. On weekends and holidays however, the island can get crowded. On the northern shore there are several tidal pools; snuggling into one of them is like taking a warm bath. Snorkelers and divers love that they can reach the reef from the shore and carouse with sea turtles, rays, and schools of colorful fish. Bring your sneakers: in about 20–30 minutes you can hike to the islet's peak, where the spectacular ruins of an old lighthouse await. Views of the surrounding Caribbean are sublime from the top of the structure, but you may not be able to climb its 54 steps; the lighthouse is currently being restored. Several tour operators offer excursions to the island.

The not-so-secret Secret Beach is a heavenly cove for those seeking privacy. This tiny yet beautiful horseshoe-shape stretch of sand, reached via a rambling dirt road, is calm and secluded. You can find yourself completely alone or in the company of just a few couples embracing in the crystal clear water. Amenities: none. Best for: solitude; snorkeling; swimming.

Consistently ranked one of the most beautiful beaches in the world, this stretch has snow-white sands, turquoise waters, and lush hills rising on all sides. During the week, it's pleasantly uncrowded; on weekends it fills up with day-trippers from the mainland. With kiosks selling simple dishes and vendors for lounge-chair and umbrella rentals, it's easy to make a day of it. There's great snorkeling past the old dock. Tanks on the northern end of the beach are a reminder that the area was once a military base. Amenities: food and drink; parking (no fee); showers; toilets. Best for: snorkeling; swimming; walking.

East of Esperanza, Puerto Mosquito is one of the world's best spots for a glow-in-the-dark experience with undersea dinoflagellates—microorganisms that light up when the water around them is agitated. Local operators offer kayak trips or excursions on nonpolluting boats to see the bay's light show. Look behind your boat at the twinkling wake. Even the fish that swim through and jump from the water bear an eerie glow. The high concentration of dinoflagellates sets the bay apart from other spots (including in Puerto Rico) that are home to these microorganisms. The experience is best when there's little or no moonlight; rainy nights are beautiful, too, because drops hitting the water produce ricochets that shimmer like diamonds. Note that licensed operators are prohibited from leading tours on the day before, during, and after a full moon.

Commissioned by President Theodore Roosevelt in 1909, the Culebra National Wildlife Refuge is one of the nation's oldest. The total protected area comprises some 1,500 acres of the island. It's a lure for hikers and bird-watchers: Culebra teems with seabirds, from laughing gulls and roseate terns to red-billed tropic birds and sooty terns. Maps of trails in the refuge are hard to come by, but you can stop by the U.S. Fish and Wildlife Service office east of the airport to find out about trail conditions and determine whether you're headed to an area that requires a permit. The office also can tell you whether the leatherback turtles are nesting. From mid-April to mid-July, volunteers help monitor and tag these creatures, which nest on nearby beaches, especially Playa Resaca and Playa Brava.