La Parguera is a bioluminescent bay found in the southern town of Lajas, a two-hour drive from San Juan. One of three bioluminescent bays found along Puerto Rico's coastline, the bay's glowing effect is made possible by micro-organisms called dinoflagellates, which emit a short burst of light when the water is agitated. La Parguera in Lajas is the only bioluminescent bay in Puerto Rico where swimming is allowed on most nights, with exceptions on nights with a full moon. To visit La Parguera Bioluminescent Bay, coordinate a boat or kayak tour with one of these tour providers: Hook'd on Adventure, Parguera Paradise Scuba Divers