On the Water
Mosquito Bay (Bahía Bioluminiscente)
The world's brightest bioluminescent bay
No swimming
Reported dark. The bay's glow has faded since July and it is in its third blackout this century; Puerto Rico's natural resources department (DRNA) is investigating. Ask your tour operator before booking. Our report, Oct 10
Mosquito Bay (Bahía Bioluminiscente) lies on the south coast of Vieques. Its glow comes from a dense population of dinoflagellates (single-celled organisms that flash blue-green when the water moves) held in the bay by its narrow mouth and the mangroves around it.
The glow is brightest on dark, moonless nights. Sunscreen and bug spray are discouraged in the water.
- Getting there
- Licensed night kayak or electric-boat tours only, from Esperanza
The moon tonight, Fri, Oct 16
Waxing crescent, 34% lit. The glow has been reported faint or absent, whatever the moon: ask your tour operator before booking. Next new moon: Nov 9.
The reserve is managed by Puerto Rico's natural resources department (DRNA)
Sources: Guinness World Records: brightest bioluminescent bay (opens in a new tab)PuertoRico.com: Puerto Rico's bioluminescent bays (opens in a new tab)
787daily guide · checked Oct 2026 · Report a correction