Locals claim that this magnificent bay, a designated wildlife preserve about 2 miles east of Esperanza, has the highest concentration of phosphorescent dinoflagellates not only in Puerto Rico, but in the world. A trip through the lagoon – take a tour – is nothing short of psychedelic, with the movement of your kayak, paddle, electric boat, even fish, whipping up fluorescent-blue sparkles below the surface. Reservations for tours are essential in high season; the best time to go is at new moon.
You can drive east on the rough Sun Bay road and stop for a view (parking well back from the water and mangroves). However, an organized trip will give you far more opportunity to really take in the spread of phosphorescence. Guides offer a wealth of information on the phenomenon as well as the flora and fauna. Look for birds including pelicans, frigate and cuckoos. In the waters below, small sharks and rays are among the fish stirring up the light show.
There’s another inlet to the east, Barracuda Bay, that’s also filled with dinoflagellates, but tour operators don’t venture out that far.