Visit the Vieques Biobay by Electric Boat

Update June.8, 2018- Post Maria- The electric boat was damaged in the hurricanes. No electric boat tours happening at this time. Only kayaking.

Perhaps you have about the “glowing waters” here in Puerto Rico. In a couple different places around the island, we have bays that contain tiny, single-cell organisms called dinoflagellates (specifically the species Pyrodinium bahamense) that are bioluminescent. Bioluminescence is the production and emission of light by a living organizm. Each one makes a sparkle when agitated. When you have a bay full of them, the water practically glows when moved. Locally, these bays are called bio bays.

The one in Vieques, Bahía de Puerto Mosquito (Mosquito Bay), is located on the southern shore of the island. Of all the bio bays in Puerto Rico, Mosquito Bay is the brightest and most protected. It is worth planning on spending at least one night on Vieques to see it.

It used to be that you could get to Vieques and see the bio bay without spending the night. But that is no longer true. Now, you need to stay overnight. But that is not a bad thing … Vieques has loads of beautiful beaches, and some other interesting things to do to keep you busy. And once night falls, you head to the biobay. There are two ways to see this bay … either by kayak, or by electric pontoon boat with Island Adventures.

Island Adventures has been doing this bio bay boat tour for many years. We have been on it a number of times. It is fun, easy, and educational. It is great for people with disabilities, or kids too young to kayak.

Vieques Biobay Mosquito Bay

The Pre-Tour

You meet your tour group at the Island Adventures office (though other pick up locations are possible). Here, they have a group area where they show you a movie, and give a brief talk about the organisms you will see on your trip into the bio bay. Their presentation is interesting and educational. All around their presentation area, they have murals of the bay and star constellations. They had clean restrooms (which you should use because these are the last you will see until you get back after the tour, about 1½ hours later). They also have a gift shop and a restaurant.

Next comes the part of the tour that will either enjoy as part of the adventure, or completely hate. You get onto this old school bus and head off for the bio bay. You are on this BOUNCY bus ride through the dark for about 15 minutes until you arrive at the biobay. Kids love this part, older people … not so much. But it is the only way in to get to where the electric boat is docked.

At The Bio Bay

Once you get off the bus, you get onto this flat, electric pontoon boat and ride into the bay. This bay area has very few houses around it, so there is not much light pollution. The bay is also usually calm, so no waves to worry about getting seasick. They use electric motors, so it eco-friendly, and extremely quiet.

You can notice the glow around the boat immediately. The dinoflagellates glow when they are disturbed, so the wake of the boat glows. It looks almost fake, like there must be light on under the boat. Another cool thing is when the fish in the bay are frightened by the boat, they swim off and leave a glowing trail behind them. Really neat!

They stop the boat in a nice dark section of the bay, and the crew tells you about the bay, mangroves and the dinoflagellates (those are the organisms that make the bay glow). The guys on the boat are knowledgeable, interesting, and entertaining. They bring up buckets of water so you can play in it and make it glow. Have it run down your arm — it is like sparkly glitter — really cool. They also let you stand on back of boat ladder and kick feet in water to make splashes.

Vieques Biobay Mosquito Bay

We tried getting photos, and even through the glow is very bright, it is difficult to get any useful shots. If you want to try, you should set your camera to ISO 1200 or higher, turn the flash off, and set it for a long (4 or more seconds) exposure. But because the boat is moving, any picture you get will probably be blurred anyway. The wake of the motor will probably be the best photo oppertunity.

After everyone is done making the water sparkle, the crew pointed out the different constellations to us. It was nice and dark in the bay area, so you should be able to see tons of stars. They use a bright LED pointer so you can really see them. Beautiful. The stars where almost as beautiful as the sparkles in the water.

After looking at the stars, they take you back to shore. There you get onto the BOUNCY bus which takes you back to the Island Adventures office. All in all, takes about 1¼ hours.


The price of this trip is around $60 per Adult, and $40 for kids (age 3-12).

If you're happy, let them know it — Don't forget to tip your your bartender, tour guide or trip operator if you enjoyed yourself. Gratuities are appreciated and typically aren't included in the price they charge you.

They offer tours every night, except for about 6 nights around the full moon. Check our bio bay calendar for the best viewing nights.

If you want to wear insect repellent, make sure it is eco-friendly, so as to not harm the bio bay.

You can call Island Adventures at Tel: 787-994-5020 for more information or to make a reservation.

You can get more information on the Island Adventures web site or on their Facebook page.

Use this map to locate places mentioned in this article. You can click on a placemark to view the GPS coordinates for that place. assumes no responsibility regarding your safety when participating in the activities described in this article. Please use common sense! If your mother or that little voice in your head tells you that you are about to do something stupid … then don't do it! Read more about Safety →

Comments & Discussion Leave a Comment »

There are 5 comments on this article. Add to the Discussion »

I was a Tour Guide for Island Adventures back in 2011-2012. I also worked doing the kayak tours as well, though the kayak tours are fun and are somewhat educational, The Island Adventure tours are more family-inclined and science driven. You can never go wrong being in a glowing body of water on an Eco-Friendly boat with a crew who is fun, energetic and professional! My favorite part of working with them was teaching my groups tourists/passengers about the stars and constellations! I'd give anything to be on the tourist end of this tour! Im certain I'd love it even!more than I did my job!

Comment by Ydeisha Hernandez Perez on 24 Apr 2017

The only company that does the Vieques biobay that goes and comes back the same day is called "PR Tour Desk". They don't go every day, so contact them and ask if they are going while you are here.

Comment by Gwenn on 29 Mar 2017

Hello, My husband, my 8 month old daughter and I am visiting Puerto Rico from 27th April to 2nd May.We want to take the bio bay Vieques tour by electric boat and we want to return the same day to San Juan as we are staying in a hotel in Isla Verde. Can you please suggest a tour ?

Comment by Chandrika Chakraborty on 29 Mar 2017

You can do the Fajardo bio bay and return to SJ the same night no problem. It is just a 20 min drive from El Yunque. But Vieques is a separate island, so you need transportation, which is not available after bio bay viewing. There is only one company (PRTourDesk) that occasionally makes a boat trip over and back the same evening.

Comment by Gwenn on 17 Mar 2017

Can you tell me why you need to stay overnight now? We are staying in San Juan, and want to do a day trip to the rainforest and bio bay - would like to do it all in one day, but not necessarily all in one tour (we like to explore on our own, if possible). Thanks!

Comment by Amy on 17 Mar 2017

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