Which bio bay should you book?

The three bays side by side

Checked November 8, 2026. Prices exclude tax unless noted.

Laguna Grande, Fajardo: the easy one from San Juan

Laguna Grande is the bay most San Juan visitors book, because it is the only one you can do as an evening trip and still sleep in your own bed. Kayaking Puerto Rico puts it "about one hour" from San Juan by car. Tours leave from Las Croabas, a small fishing village at the far end of Fajardo, and paddle through a mangrove channel into the lagoon. Kayaking Puerto Rico notes the channel entrance sits inside the Las Cabezas de San Juan Nature Reserve.

What the paddle is like: two people share a sit-on-top kayak, and the tour runs about two hours, including a short lesson on land. It is a real paddle, in the dark, sometimes against wind. Kayaking Puerto Rico warns the bay can have strong winds and currents, and seasonal sargassum.

Can you swim? No. Kayaking Puerto Rico's tour page lists "Swimming is not allowed," and its FAQ explains why: people jumping in stir up sediment from the bottom of the lagoon. Yokahú Kayak Trips says swimming is prohibited and cites a 2007 DRNA ban. We have not found that DRNA document itself.

Prices and times. Kayaking Puerto Rico charges from $70 per person; check-in from October to January is 5:45 p.m. or 8:00 p.m., and it asks you to arrive 20 minutes early. Yokahú charges from $55 for a two-hour tour, runs Monday to Saturday (no Sunday tours), and serves snacks and drinks after. Other Fajardo operators in our research list the bay at $55 to $75.

Ages. Both companies take children from age 6. At Kayaking Puerto Rico, kids 6 to 13 share a kayak with an adult. Yokahú does not take pregnant guests.

Good for: anyone staying in San Juan, Condado, Isla Verde or Fajardo. Skip it if: you cannot paddle for close to two hours, or you have a child under 6.

[ISAIAH: first-hand note here. Las Croabas at dusk: where you parked, how the check-in tents looked, and how dark the lagoon really was on the night you went.]

Mosquito Bay, Vieques: famous, but check its glow first

Mosquito Bay (Bahía Puerto Mosquito) is the bay with the reputation. Guides and operators call it the brightest in the world, and Black Beard Sports' site describes it that way. We are not repeating that as fact in 2026, for a simple reason.

What happened in 2026. Primera Hora reported on October 9, 2026 that the bay's bioluminescence had declined steadily since July and reached zero in the last week of September, according to weekly plankton counts by the Vieques Conservation and History Trust. The main glowing organism was detected again in low numbers in early October. On October 12, Radio Isla quoted the DRNA Secretary saying his staff were evaluating a possible reduction in the bay's bioluminescence. On October 18, Primera Hora reported the glow had still not come back. The bay has gone dark before (2014, and after Hurricane María in 2017) and recovered, but the Trust gave no timeline. We found no closure order and no report that tours had stopped.

What this means for you: before you book a trip to Vieques for the bay, ask the operator directly how bright the bay has been this week, and what they do if it is dim. We will update this page when the Trust or DRNA reports a recovery.

Getting there. You cannot drive to Vieques. You drive to the ferry terminal in Ceiba, then take the ferry, which the official ferry site puts at about one hour. Rental cars cannot go on the ferry; only vehicles owned by Vieques or Culebra residents can. The adult fare is $2.00 one way on the official rates page, but the government has scheduled a higher fare for non-residents on the island routes from December 31, 2026, already postponed twice, so check at checkout. The official schedule (valid to November 30, 2026) shows the last ferry from Vieques to Ceiba at 9:30 p.m. every day. Most bay tours start at 7, 8 or 9 p.m., so plan to sleep on Vieques. Abe's Snorkeling says its 6 p.m. tour, offered in high season, leaves enough time for the 9:30 p.m. ferry. You can also fly to Vieques. Read our Culebra ferry guide for how the island ferries work.

Can you swim? No. Abe's Snorkeling's FAQ: "Swimming in Bahía Mosquito is strictly prohibited." It also says only tour companies with DRNA permits may enter the bay, from 6 p.m. to midnight.

Prices and times. Abe's charges $70 for adults, $50 for kids 4 to 11, infants free, for a two-hour kayak tour at 6, 7, 8 or 9 p.m.; all ages are welcome. Other Vieques kayak operators in our research list $60 to $65. Black Beard Sports uses clear-bottom kayaks. Tours meet in Esperanza or nearby, so check your confirmation.

Good for: travelers already spending at least one night on Vieques. Skip it if: you are based in San Juan and only have one evening.

La Parguera: the one where tours include a swim

La Parguera is a small waterfront town in Lajas, on the southwest coast. Travel guides put it about two to two and a half hours from San Juan, which makes it a poor day trip from the capital but an easy evening from Cabo Rojo, Guánica, Yauco or Rincón.

Can you swim? Tours here sell a swim, which you will not find at the other two bays. Paradise Scuba & Snorkeling's bio bay tour includes about 30 minutes of swimming in the bay and says "ALL PARTICIPANTS MUST KNOW HOW TO SWIM." Parguera Glassbottom Kayaking sells a one-hour swimming tour. A 2023 newspaper piece republished by the University of Puerto Rico at Mayagüez said DRNA buoys mark a swimming area. We have not found the official rule in a DRNA document, so ask your operator two things when you book: where in the bay you swim, and whether swimming is allowed on your date.

Closed nights. Primera Hora reported in June 2023 that DRNA Administrative Order 2023-02 closes the bay "durante tres días de Luna llena en cada ciclo lunar" (three full-moon nights each lunar cycle). We could not find the order on DRNA's website and have not confirmed it is still in force, so ask the operator whether your night falls in a closure.

How dim is it? Guides commonly describe La Parguera as the dimmest of the three. Glow at every bay changes night to night with moon, weather and water, so treat any ranking as a general description, not a promise.

Prices and times. Paradise Scuba charges $70 per adult and $35 for children 5 and under (infants under 1 free). It runs Mondays, Wednesdays and Fridays, with check-in at 8:00 p.m. from November to January. Its sunset cruise ($85) adds a mangrove ride, a swim stop at Cayo Caracoles and about 30 minutes in the bay. Parguera Glassbottom Kayaking does not list prices on its site; its boat-and-kayak tour runs 1 hour 45 minutes for all ages, and needs at least 4 people to run.

Good for: west and south coast stays, swimmers, families with confident swimmers. Skip it if: you are in San Juan without a car, or nobody in your group swims well and you only want the swim tour.

[ISAIAH: first-hand note here. The drive from Yauco to La Parguera at night (time it), where you parked by the docks, and what the swim felt like.]

Moon, weather and the closed nights

The glow comes from tiny plankton that flash when the water moves. Moonlight washes it out, so the darkest nights, around the new moon, are best. Kayaking Puerto Rico says the glow depends on the moon phase and that bioluminescence "is unpredictable and subject to change."

Here are the new and full moons through April 2027, from the U.S. Naval Observatory, converted to Puerto Rico time (AST, UTC-4; Puerto Rico does not change its clocks).

If your trip lands on the night before, the night of, or the night after a full moon, ask a La Parguera or Vieques operator whether they are running. At Laguna Grande we found no closure rule; operators run on bright nights, and Yokahú says it has "solutions to make it darker."

Every operator we checked makes the weather call itself. Abe's says it cancels when conditions are extreme or dangerous; its FAQ does not list rain alone as a reason.

What to bring

• Clothes and water shoes that can get wet, plus a towel and dry clothes for the ride home
• Nothing valuable; Kayaking Puerto Rico warns not to bring anything that cannot get wet
• No DEET bug spray in the water. Abe's asks for DEET-free spray only, and Kayaking Puerto Rico says DEET and skin lotions can harm the glowing organisms
• Skip sunscreen at night; Abe's notes it is a contamination concern in the bay
• A swimsuit, if you booked a La Parguera swim
• Money for a tip; Parguera Glassbottom lists tips as not included

Photos: Kayaking Puerto Rico lists a cell phone on its what-to-bring list, but warns that anything you bring may get wet; Yokahú does not recommend cameras.

How to book a good tour

Book a licensed operator. Bio bay tours in Puerto Rico are run by companies that need a Tourism Company nautical certificate and a DRNA permit. The Tourism Company publishes a list of companies with current nautical certificates (the file we read is dated October 1, 2026), and all five operators named in this guide hold a current certificate on it. DRNA does not publish a list of its permit holders, and we have not yet confirmed any operator's DRNA permit. Ask the company for its DRNA permit before you pay.

Read the cancellation terms. Kayaking Puerto Rico and Yokahú need 48 hours' notice for a refund. Abe's needs 24 hours. If the company cancels for weather, Kayaking Puerto Rico and Abe's offer a new date, another tour or a full refund. If the tour runs and you skip it because of rain in San Juan, you pay.

Ask about the moon and the glow. None of the operators we checked promised a refund for a dim bay or a bright moon. Book a dark night and ask before you pay.

Mind the minimums. Kayaking Puerto Rico needs six guests; Parguera Glassbottom needs four. If the minimum is not met, Kayaking Puerto Rico calls to reschedule or cancel without penalty.

FAQ

Which bio bay is the brightest? Mosquito Bay on Vieques has long been called the brightest, but its glow measured zero in late September 2026 and had not recovered as of October 18, 2026, per Primera Hora. Brightness at every bay changes with moon, weather and water.

Can you swim in a bio bay in Puerto Rico? At Laguna Grande and Mosquito Bay, no; operators prohibit it. At La Parguera, tours include a swim, but we have not seen the official rule text, so confirm with your operator.

Do you need a tour? At Mosquito Bay, yes: Abe's says only permitted tour companies may enter. At the others, booking a licensed tour is the safe and legal way to go.

How long is the Fajardo bio bay kayak tour? About two hours, including a short lesson.

Is the bio bay good for kids? Fajardo kayak tours start at age 6. Abe's on Vieques welcomes all ages; small children sit with a parent. In La Parguera, the boat-and-kayak tour takes all ages, and the swim tours require that participants know how to swim.

Is it worth going on a full moon? You will see less glow. La Parguera and Mosquito Bay may not run at all around the full moon; see the table above.

Do tours run in the rain? The operator decides. Abe's cancels when conditions are extreme or dangerous, and Kayaking Puerto Rico warns that if the tour goes out and you stay home, you are still charged.

Can I do Mosquito Bay as a day trip from San Juan? Only on the early tour Abe's offers in high season, if you catch the 9:30 p.m. ferry. Otherwise, plan to stay on Vieques.

Still deciding? Staying in San Juan: Laguna Grande. West or south coast, or you want to swim: La Parguera. Already sleeping on Vieques: Mosquito Bay, after checking the glow. Then pick a dark night from the moon table.