Vieques is the larger of the two Spanish Virgins, and Mosquito Bay is why most people book it. Stay overnight. The bio-bay kayak is after dark, and the last ferry won't wait because your tour ran late. Wilder beaches and former Navy land make the island feel emptier than Culebra. Region page: Vieques & Culebra.
The bay, then the rest
Brightness depends on the moon and recent rain. A bright night here is the best bio bay on the island. A washed-out night is still a kayak in the dark. Don't treat it as a guaranteed spectacle. Daytime is beaches and a slower town.
Booking on adventuro
Night kayaks are beginner-friendly if you swim. Open the Book here tab, then lock the ferry or plane around the session, not the other way round.