Even in the Caribbean, known for its turquoise waters and sugar soft sands, secluded oases are becoming increasingly rare. But off the eastern shore of Puerto Rico, less than a 30-minute flight from bustling San Juan, we discovered two treasures: Vieques, population 10,000 and Culebra, with barely 2,000 people.

Both deliver the Caribbean of long-ago--a sun-swept seascape devoid of high-rise hotels and heaving traffic. Instead of partygoers swaying to salsa beats on packed dance floors, nightlife on these shores means swimming in luminescent bays or listening to the palm fronds rustle in the breeze. Without duty free shopping malls and make the scene crowds, these islands won't please everyone-- just those families who want eco-adventures and spectacular beaches plus a good property in each place offering civilized services.

Vieques
As we kayaked in Mosquito Bay on a nearly moonless night, each of our strokes cut an electric blue ribbon in the water. Just ahead a flash of neon-like color betrayed a fish zig-zagging close to the surface. Amazed at how movements in this bay morphed into streaks of light, we jumped in, floated on our back, and waved our arms and legs to fashion foamy glowing "water" angels.

Instead of paddling from the kayak, our group happily splashed in the bay, creating strobes of light quickly followed by "wow" and "look at that." Mosquito Bay, nicknamed Bio Bay, is one of the Caribbean's best--some say one of the planet's best-- examples of bioluminescence. Disturb the mega-millions of dinoflagellates living in these waters and they light-up like fireflies, a mesmerizing experience.

On our second favorite Vieques adventure, we biked the back roads, winding through areas formerly off-limits as part of a U.S navy base. The huge bunkers we pedaled past once housed ammunition for practice bombing missions, but now bat colonies hung from the ceilings. With the cessation of artillery drills, and the departure of the Navy came the establishment in 2001 of the Vieques National Wildlife Refuge, a service that works to clean up the former target areas. Now more than half of Vieques, or 18,000-acres of the island's 32,000-acres remain under control of the refuge, which has opened two new beaches since 2001.

Vieques' has many alluring beaches, especially mile-long Sun Bay Beach, where coconut palms and sea grape trees line the white sands, and secluded Green Beach, our reward for our morning's biking work-out.

The place to stay on Vieques: Wyndham Martineau Bay Resort & Spa, the largest of Vieques properties with 156-rooms. The beachfront hotel sports a casually elegant feel, comfortable rooms, but, alas, on my visit soon after their April 2003 opening, mediocre food. We're told the kitchen has improved. But just in case, the casual M Bar & Restaurant, across the street, serves very good fusion cuisine that mixes Spanish, Cuban, and island influences to serve up imaginative entrees such as sea bass with
pumpkin, sweet plantains and fava beans.

Culebra
Culebra, much less-populated than Vieques, is even more laid-back. There are two main reasons to come here: swimming at Flamenco Beach and snorkeling off Carlos Rosario beach.

Named for the pink flamingos that once nested in the nearby lagoon, Flamenco Beach, part of a public park and popular with locals, is a nearly mile-long horseshoe curve of wide sands sporting modest waves. Concessionaires sell soft drinks and rent chairs and the park offers overnight camping spots so close to the sea that you can fall asleep to the sound of breaking surf.

After walking from Flamenco Beach about 3/4 mile up a hill and down to the next cove, we came to Carlos Rosario Beach, a sliver of sand that serves as the departure point for one of the island's top snorkeling tours. We hovered over acres of watery gardens blooming with colorful orange brain, purple fan, and thick brown elkhorn and stag coral.

The best place to stay: Club Seabourne, an unassuming boutique hotel with 14 rooms and one villa plus some very good food. Be sure to try the lobster spring rolls.