Fodor's Expert Review Bioluminescent Bay

As soon as the sun sets, large and small boats line the dock to take visitors out to view the Bioluminescent Bay. Microscopic dinoflagellates glow when disturbed by movement, suffusing the waves with thousands of starlike points of light. The bay's glow has been diminished substantially by pollution—both light pollution from nearby communities and water pollution from toxic chemicals dumped into the bay and constant boat traffic. This bay isn't as bright as the one in Vieques, but it's the only swimmable bio bay on the island. While it's not necessary to make a reservation—plenty of operators try to rustle up customers on the docks around sunset—Paradise Scuba runs the most reputable excursions in the area. Visit their dive shop for more information.