Just six miles off the coast of mainland Puerto Rico, Vieques is home to the brightest bioluminescent bay in the world.

The unearthly glow of Mosquito Bay, on the south coast of the island, is created by billions of tiny single cell aquatic organisms called dinoflagellates. 

Dinoflagellates produce light through a chemical reaction that brightens considerably when they become agitated. 

There are 1,000,000 to 2,100,000 dinoflagellates per gallon of water in Mosquito Bay, one of the highest concentrations in the world.

The lack of light pollution on the island also intensifies the glow.

The dock on Vieques (Shutterstock)
A beach on Vieques, Puerto Rico (Ethan Jackson/Unsplash)

The bay glows brightest under a new or crescent moon. 

Local tour operators offer night-time kayak tours where each dip of your paddle sets off a spectacular light show and leaves a throbbing glow of blue light in your wake. 

Condé Nast Traveller named it one of the 2020’s seven wonders of the world.

The Guinness Book of World Records named it the brightest bioluminescent phenomenon in the world in 2006.

Try to get one of the glass-bottomed kayaks for a fully immersive experience.

Wild horses on Vieques (DiscoverPuertoRico.com)
A tank abandoned on a beach on Vieques (Shutterstock)

Vieques is only a thirty-minute ferry ride from Cieba but warrants a much longer stay.

60% of the island is covered by the Vieques National Wildlife Refuge, one of the most ecologically diverse wildlife refuges in the Caribbean.

Here you’ll find deserted beaches, mangrove wetlands, lagoons and upland forests. It’s one of the best places to spot the endangered Antillean manatee as well as four species of sea turtles.

And untamed pino faso horses, abandoned by Spanish colonisers and left to flourish here, walking along the beaches.

For more information about Vieques and Mosquito Bay, visit DiscoverPuertoRico.com

Main image: Paddling through the bioluminescence at Mosquito Bay of Vieques (DiscoverPuertoRico.com)