Puerto Rico's Bioluminescent Bays
Did you know that three of the world’s five year-round bioluminescent bays are in Puerto Rico? These rare natural wonders create a breathtaking glow-in-the-dark experience that every visitor should witness at least once. Located in Mosquito Bay, Laguna Grande and La Parguera. The other two are located in Luminous Lagoon in Jamaica and Halong Bay in Vietnam.
What is a Bioluminescent Bay?
A bioluminescent bay (bio bay) is a body of water that glows at night due to the presence of dinoflagellates, single-cell marine plankton that emit a blue-green light when disturbed.
The brightness of a bio bay depends on:
- Water temperature
- Moon cycle & darkness of the night
- Water currents & salinity
- Ecological conditions & mangrove health
The best time to visit is during a new moon, when the darkness enhances the glowing effect.
Where Are Puerto Rico's Bioluminescent Bays Located?
- Mosquito Bay
Located on the island of Vieques, east of the coast of Puerto Rico. This bay is the brightest and best-known bioluminescent bay in the world, it has the highest concentration of dinoflagellates, ranging from 700,000 to 2,100,000 per gallon of water—creating an unmatched glow. Recognized in 2006 as the brightest bioluminescent bay in the world.
Best Way to See It: Clear-bottom kayaking tours. - Laguna Grande
Located on the northeastern part of Puerto Rico, in Fajardo. This mangrove-surrounded lagoon offers a mystical, glowing experience and is easily accessible from San Juan. Swimming is not allowed, but kayaking tours provide an up-close experience.
Best for travelers who want a short trip from San Juan. - La Parguera
Located southwestern part of Puerto Rico, in the town of Lajas. Unlike Mosquito Bay and Laguna Grande, swimming and snorkeling are allowed here. Boat tours available, making it a great choice for families and larger groups.
Best for those looking for a more interactive experience.
Swimming is not allowed in Mosquito Bay and Laguna Grande; you can swim and snorkel in the bay at La Parguera. Remember to plan and book your tour around the moon cycle, the darker the night, the brighter the bioluminescence.
When is the Best Time to Visit?
- Visit During a New Moon – Darker nights make the glow more visible.
- Go After Sunset – Tours usually start between 7 PM and 10 PM.
- Avoid Rainy Days – Heavy rain can dilute the water’s salinity, temporarily reducing brightness.
Tour Prices: Range from $45 to $135 per person, depending on location and tour type (kayaking vs. boat).
How to Visit Responsibly
To help protect Puerto Rico’s bio bays and ensure future generations can enjoy them:
- Choose Eco-Friendly Tours – Look for operators that use clear-bottom kayaks or electric boats.
- Avoid Sunscreen & Bug Spray – Even reef-safe products can harm the fragile dinoflagellates.
- No Flash Photography – The glow is best captured with long-exposure settings on cameras.
- Do Not Touch the Water (except in La Parguera) – Preserving the ecosystem is key to maintaining the bio bays’ magic.
Recommended Bioluminescent Bay Tours
Here are some reliable tour operators offering kayaking and boat trips to Puerto Rico’s bio bays:
Fajardo (Laguna Grande)
- Kayaking Puerto Rico – (787) 435-1665 | (787) 245-4545
- Pure Adventure – (787) 202-6551 | (787) 314-4347
- Island Kayaking Adventures – (787) 444-0059
- Peniel Access Eco Tours – (787) 463-1940
Vieques (Mosquito Bay)
- Yokahu Kayak Trips – (787) 604-7375 | (787) 863-5374
- Las Tortugas Adventures – (787) 809-0253 | (787) 637-8356
Lajas (La Parguera)
- Eco Action Tours – (787) 791-7509 | (787) 640-7385
Other Resources
Traveling to Puerto Rico? Get the Puerto Rico (National Geographic Adventure Map), includes locations of airports, harbors, anchorages, ferry routes, and toll plazas take the guesswork out of travel around the islands. Visitor centers are also marked for travelers seeking additional resources.
