Quick answer
La Parguera is the bioluminescent bay on Puerto Rico’s southwest coast, in the municipality of Lajas — one of the island’s three bio bays.
- About 2½ hours from San Juan, about an hour from Aguadilla, without traffic.
- Some licensed boat tours have offered a swim here (swimming is not allowed at Mosquito Bay); confirm with the operator before you book.
- Since June 2023, a DRNA order closes the bay for three full-moon days each lunar cycle.
- Best on dark nights near the new moon: Oct 10, Nov 9 and Dec 8, 2026.
La Parguera is one of three bio bays in Puerto Rico.
In this article, I will go over everything you need to know about La Parguera:
– What is bioluminescence?
– What is La Parguera Bioluminescent Bay?
– Where is La Parguera Bio Bay located?
– How to get to La Parguera Bio Bay from San Juan?
– Can you swim in La Parguera Bioluminescent Bay?
– Which is better: kayaking or boat tour?
– Can you go to La Parguera without a tour?
What is bioluminescence?
Bioluminescence is when living organisms emit light due to a chemical reaction.
Fireflies are a common example of bioluminescence.
It happens often in marine animals, fungi, bacteria, and land arthropods.
This chemical reaction varies in color, but blues and greens are some of the most common in the animal kingdom. Some species can even glow red!
The purpose of bioluminescence can be for camouflage, mating, repelling predators or attracting prey.
The glow in the water of a bioluminescent bay is produced by millions of single-celled plankton called dinoflagellates.
They emit light when stimulated as a defense mechanism.
Dinoflagellates can be found throughout the ocean. But, only when they concentrate in large quantities and the environmental conditions are ideal, the glow will be visible to the human eye.
Below is a video that shows bioluminescent water and ocean animals:
Puerto Rico has three different bioluminescent bays. Learn more about them in our guide to Puerto Rico’s bioluminescent bays.
What is La Parguera Bioluminescent Bay?
La Parguera is a bio bay located on the south coast of Puerto Rico, in the town of Lajas.
The small entrance to the La Parguera bio bay traps millions of dinoflagellate plankton inside it. These plankton then start to multiply since they can’t escape the bay. The high concentration of plankton in the bay is what allows humans to see the bioluminescent light when moving the water.
The calm current, water temperature, mangroves, shallowness of the bay and narrow entrance make it possible for the bioluminescence to occur year-long.
I recommend that you read our article about when is the best time to see the bioluminescence in Puerto Rico as the visibility of the bioluminescence is better during certain months.
Below is a video that shows La Parguera Bio Bay:
The bay is managed by Puerto Rico’s Department of Natural and Environmental Resources (DRNA). To cut illegal motorboat traffic and protect the glow, a June 2023 DRNA administrative order closes the bay for three full-moon days in every lunar cycle.
Where is La Parguera Bio Bay located?
La Parguera Bio Bay is located on the coast of Lajas, a southern town in Puerto Rico.
See La Parguera Bioluminescent Bay’s location on Google Maps below:
How to get to La Parguera bio bay from San Juan
Drive. La Parguera is about 2½ hours from San Juan without traffic (about 2 hours 35 minutes from Old San Juan using OpenStreetMap routing), and about an hour from Aguadilla. Tours run after dark, so consider staying in the southwest rather than driving back to San Juan the same night — browse places to stay in Lajas.
See Cabo Rojo and Mayagüez for places to base yourself.
Can you swim in La Parguera bioluminescent bay?
La Parguera is the Puerto Rico bio bay where some licensed boat tours have offered a swim; swimming is not allowed at Mosquito Bay and isn’t part of Laguna Grande tours. Rules and operator offerings can change, so ask before you book, and never go into the water on your own at night.
Which is better: kayaking or boat tour?
The best way to see the bioluminescence is by kayak.
Kayaking is more interactive.
Can you go to La Parguera without a tour?
Go with a licensed operator. The bay is managed by the DRNA, which has cited unpermitted visits and illegal motorboat use as problems, and the bay is closed for three full-moon days each lunar cycle — browse La Parguera / Lajas bio-bay tours.
Frequently asked questions
Can you swim in La Parguera bio bay?
Some licensed boat tours have offered a swim at La Parguera, unlike Mosquito Bay, where swimming is banned. Confirm with the operator before you book.
Is La Parguera bio bay closed during the full moon?
Yes. A June 2023 DRNA order closes the bay for three full-moon days each lunar cycle.
How far is La Parguera from San Juan?
About 2½ hours without traffic. It is about an hour from Aguadilla.
Is La Parguera the brightest bio bay?
No. Guinness World Records lists Mosquito Bay on Vieques as the world’s brightest.
When is the next new moon?
October 10, November 9 and December 8, 2026, then January 7, 2027 (US Naval Observatory).
Final thoughts
La Parguera is the bio bay to choose if you are staying in the southwest or want a tour that may include a swim. Go on a dark night near the new moon and avoid the full-moon closure.
The glow is easiest to see when the sky is dark. Around the new moon the moon is down for the whole evening. In the days after the full moon, the moon rises later each night, so early-evening tours can still be dark; around the full moon itself, the moon is up all night and the glow is much harder to see. Since June 2023, a DRNA order closes La Parguera’s bay for three full-moon days every lunar cycle.
| New moon (darkest skies) | Full moon |
|---|---|
| Oct 10, 2026 | Oct 26, 2026 |
| Nov 9, 2026 | Nov 24, 2026 |
| Dec 8, 2026 | Dec 23, 2026 |
| Jan 7, 2027 | Jan 22, 2027 |
| Feb 6, 2027 | Feb 20, 2027 |
| Mar 8, 2027 | Mar 22, 2027 |
| Apr 6, 2027 | Apr 20, 2027 |
| May 6, 2027 | May 20, 2027 |
| Jun 4, 2027 | Jun 18, 2027 |
| Jul 3, 2027 | Jul 18, 2027 |
Compare all three in our guide to Puerto Rico’s bioluminescent bays.
Sources we checked
Checked in October 2026. Where a fact could not be confirmed against a primary source, we removed it or said so.
- Metro Puerto Rico (June 8, 2023): DRNA Administrative Order 2023-02 closes La Parguera’s bio bay for three full-moon days every lunar cycle
- Para la Naturaleza: Puerto Mosquito, Vieques — protected reserve under the DRNA, co-managed by the Vieques Conservation and Historical Trust; licensed operators only; no swimming, jet skis or motorboats; Puerto Rico’s three bio bays
- Guinness World Records: brightest bioluminescent bay — Mosquito Bay, Vieques (2006; up to 700,000 Pyrodinium bahamense per gallon)
- US Naval Observatory: dates and times of the primary moon phases (UT; converted to Atlantic Standard Time)
- PuertoRico.com drive times (OSRM on OpenStreetMap, October 2026, free-flow, no traffic)
Originally published on PuertoRico.com (2022-10-09). Reviewed and updated October 2026: facts were checked against the sources above.