Bioluminescent Bay (Mosquito Bay)

The basics

Any contact with the water—by the boat, a paddle, or a part of the body—makes the water glow bright neon blue and green. Jump in for a neon-lit swim, cruise over the water in a pontoon boat, or board a kayak to paddle through the bay. Bioluminescent Bay (Mosquito Bay) tours typically allow you to learn about the biology of dinoflagellates and their interaction with the Vieques ecosystem.

Things to know before you go

• Nighttime tours require a stay overnight on Vieques Island; the tour company can typically provide recommendations for hotels or guest houses.

• Be sure to apply bug repellent, as Mosquito Bay lives up to its name.

• La Parguera Bioluminescent Bay is the only bioluminescent bay in Puerto Rico where swimming is permitted.

How to get there

Mosquito Bay is located on the southern shore of Vieques, which you can reach by ferry from Fajardo on the main island of Puerto Rico. Reaching the bay is an adventure in itself that requires a 10-minute drive down a very bumpy and rutted 4WD track. Tours of Mosquito Bay typically provide transportation to the bay from the town of Esperanza on Vieques Island.

When to get there

The dinoflagellates in Bioluminescent Bay are active year-round but are best seen during the new moon, when the sky is darkest and the water glows brighter by comparison. Tours typically do not operate the day before, during, and after the full moon, when the organisms are difficult to see.

Must-see Vieques attractions

Isla Vieques was under the control of the US Navy for 60 years and thus remains largely undeveloped. The small island is home to unspoiled rainforest dotted with pristine beaches and archaeological sites including the Hombre de Puerto Ferro, where skeletal remains up to 4,000 years old were discovered. Along with the famous bio bay, Vieques is host to some excellent snorkeling, especially at Blue Beach (Bahía de la Chiva).

Ways to explore

Any contact that the water in Bioluminescent Bay makes—whether it's with a boat, paddle, or a part of the body—makes it glow bright neon blue and green. As one of the island’s top attractions, there is a wealth of tours that depart for the bay: Jump in for a neon-lit swim, cruise over the water in a pontoon boat, or board a kayak to paddle through the bay. Clear-bottom kayaks are a great way to admire the lights without getting wet.

Accessibility

Most Bioluminescent Bay experiences involve boarding a small, non-motorized boat, few of which can accommodate wheelchairs.

Age limits

These nighttime tours on open water are typically not recommended for kids 7 and under.

What to pack

Be sure to bring a waterproof bag to keep your valuables in, as you’re sure to want to capture this natural phenomenon on camera.

What to wear

As its name suggests, there are lots of mosquitoes here, so wear long-sleeved clothing when you’re not in the water to protect yourself from bites.

Not allowed

You cannot use chemical-based insect repellent, as this is harmful to the dinoflagellates that create the bioluminescent effect.

Amenities

Amenities at Bioluminescent Bay itself are nonexistent, but most boat tours provide life jackets and transportation.

Address 

Mosquito Bay is on the island of Vieques; to get there from Puerto Rico’s mainland, you can either fly from Isla Grande Airport or take a ferry from Ceiba. You must book a tour to experience the bay; most operators typically provide transportation from the town of Esperanza.

Driving

If you choose to take the ferry, you can drive to the Ceiba Ferry Terminal, which has on-site parking, or hire a driver to take you. It’s about a 30-minute ferry ride to Vieques. Once you arrive, hail one of the taxis outside the terminal and direct them to Esperanza. Alternatively, arrange to have a driver pick you up at the airport.

Public transportation

There are limited public transit options on Vieques. From the Vieques airport and ferry terminal, you can take a shared van (publico) to Esperanza, but the schedule is not fixed, and vans tend to only leave when they’re full. Your best bet is to get a taxi or hire a driver.

Best times to visit

You can only see the bioluminescence after sunset, when the night has gotten fully dark, so tours typically depart between 7pm and 10pm.

Best days to visit

To see the bay at its brightest, visit three days either side of the new moon, when the sky is least illuminated by moonlight.

Best months to visit

The reduced rainfall (and therefore cloud cover) of the dry season from December through April is the best time to visit.

Special events

The San Sebastián Street Festival in mid-January is a particularly festive time to visit Puerto Rico.