Best Bio Bay in Puerto Rico: Comparing Puerto Rico's 3 Bioluminescent Bays

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If you’re planning a trip to Puerto Rico, then seeing one of the island’s bioluminescent bays is a must-do activity! I’ve been lucky enough to do all three bio bays in Puerto Rico, so here are my recommendations on the best bio bay and what you can expect on your tours.

To be honest, all three of them are pretty incredible. And while most people claim Mosquito Bay is the best because it is brightest, my favorite was actually the experience in La Parguera! But I’ve got details on all three below to help you decide which one is best for your trip.

What is a bio bay? Bioluminescent bays are home to dinoflagellates (a type of plankton) which glow at night when the water moves. It seems magical and otherworldly, but there’s some pretty cool science behind it that you’ll learn on your tour!

Dark Photo with a shadow of a person swimming and the water around their limbs glowing. — Swimming in the bio bay in La Parguera, Puerto Rico

Where Are the 3 Bioluminescent Bays in Puerto Rico?

Puerto Rico is the only place in the world that has THREE bioluminescent bays! And depending on where you are traveling in Puerto Rico, it should be relatively easy for you to see one of them.

They are also active year-round, so you don’t have to wait for a certain time of year to see them!

Laguna Grande — Located near Fajardo on the Northeast corner of the island. It’s about an hour away from San Juan. This is the best tour to pick if you are staying in San Juan.
La Parguera — Located in Lajas on the Southwest corner of the island. It’s about 45 minutes away from Ponce. This is my favorite bio bay because the experience of swimming in it is unbelievable.
Mosquito Bay — Located on the island of Vieques. (See more about how to take the ferry to Vieques here. You will need to stay overnight on Vieques to do a bio bay tour!) This is the brightest bio bay and often cited as the best!

My Puerto Rico Bio Bay Recommendations

If you’re staying in San Juan, book this tour for Laguna Grande.
If you can swing an overnight trip to Vieques and want to go to the brightest bay, book this tour for Mosquito Bay.
If you are on the south side of the island and want to swim in a bio bay, book this tour in La Parguera.

Map of Puerto Rico’s Bio Bays

Laguna Grande (Most Convenient Bio Bay)

If you are staying in San Juan for most of your Puerto Rico trip, Laguna Grande is going to be the easiest Bio Bay tour to do. And it’s really fantastic. I recommend this tour, which is the one we did.

Because of it’s location, this is the most popular bio bay to see in Puerto Rico. And you can tell because there is a Kayak Village set up near the bio bay with huts for all the outfitters to accommodate the large number of guests.

Visiting Laguna Grande requires you to kayak in the dark through a mangrove forest. Honestly, this is pretty cool, but it also can get a little tricky since visibility is tough and you must follow the light in front of you.

Once you are out of the mangrove forest though, it opens up into a large bay where your guides will show you how to best see the bioluminescent activity. Depending on the tour you do, this will look different. On ours, they included tarps to put over our heads to see it better and gave us some free time to explore the bay on our own.

I really liked this tour and thought it was really well done! I learned a lot about the dinoflagellates that create the bioluminescence and really enjoyed the experience.

Pro Tip: If you can swing it, book a tour for this one later in the evening! The narrow stream through the mangroves can get crowded with boats, but since we were a later tour, we were some of the last to leave the bay and had less traffic jams than other groups.

Also it’s important to know that our of all the tours, this is the place that is strictest about weight limits. They actually weigh you at check-in, and several people were turned away from our tour, including one person in our group.

Pros & Cons of Laguna Grande

Pros

Super convenient to visitors to San Juan
Very efficient operation. These teams know what they are doing!

Cons

Kayaking through the mangroves can be difficult, especially if you are inexperienced.
Strict weight limits for kayakers.

Dark photo with a stream of bioluminscent water showing behind a boat — Water glowing behind boat in La Parguera

Mosquito Bay (Brightest Bio Bay)

Mosquito Bay on the island of Vieques is known as the brightest bioluminescent bay in the world!! If you’re visiting Vieques, I recommend this tour for Mosquito Bay.

Mosquito Bay is more laid back than Laguna Grande (definitely no one weighed us). To get there, we met at a meeting spot and then had to take a bus down an EXTREMELY bumpy road. Then from there we had to wade barefoot through some stinky mud to get into the kayaks, but then we were off! (Just letting you know all the not-so-great parts in advance.)

Here, you’re kayaking on in a much more open space. We booked our tour for around sunset, so we spent sunset time kayaking to the opposite side of the bay, and then once it was dark we slowly made our way back to the our starting point.

This bio bay is definitely brighter than any other one we saw. Even though our moonlight wasn’t ideal, the glowing of the phosphorescence was still pretty incredible.

I also really liked that with the tour we did, there were clear panels at the bottom of the double kayaks, so we could look down and see it as we were moving.

I really liked this tour a lot! I appreciated that it wasn’t as crowded as Laguna Grande and the kayaking part wasn’t as stressful. If are choosing between Laguna Grande and Mosquito Bay and both would make sense in your plans, I would definitely choose this one over Laguna Grande.

Pros & Cons of Mosquito Bay

Pros

Brightest bio bay in the world!
Easier kayaking.

Cons

Not convenient at all unless you are already planning an overnight stay in Vieques.

Daytime picture of water with an island of red mangrove trees. You can see the leaves and the red roots of the trees in the water. — Red mangrove trees like these are a key ingredient for bio bays.

La Parguera (My Pick for the Best Bio Bay Tour in Puerto Rico)

Ok. This one really surprised me. Anytime I told someone that we were heading to La Parguera so we could see all three of Puerto Rico’s bio bays, most people turned their nose up at this one. People told me, “It’s not as bright” and “You won’t like it as much.”

Well, I’m here to say that it ended up being my FAVORITE bio bay experience in Puerto Rico! (We booked this tour and highly recommend it!)

The bio bay in La Parguera is an entirely different experience than Laguna Grande and Mosquito Bay. First of all, you aren’t kayaking to see it. You take a chartered boat, so it’s a much more relaxing experience.

Second of all, you get to swim in it! It’s the only bio bay in Puerto Rico where you are allowed to swim.

I wasn’t sure how I was going to feel about this. Like…if boats are going in and out am I going to feel safe swimming? Was it going to be peaceful? And is it environmentally okay to be swimming in this?

To answer the first questions, yes, I felt entirely safe. The boats coming in and out were actually pretty quiet and distant.

And I learned that because of the shape of this particular bay, the dinoflagellates replenish at a rate fast enough that swimming isn’t so much of a concern here. (They also took us elsewhere to swim first to wash off anything on our skin that could harm them just in case.)

Y’all. There is NOTHING like swimming in bioluminescent water. It was SUCH a magical experience to have every move you make cause the water to glow and to be able to lift your arms out of the water and have the sparkle like stars.

I know it’s not the most popular bio bay, but for me personally, this was the best bio bay in Puerto Rico!

Pros & Cons of La Parguera

Pros

No kayaking. It’s an easy boat ride to the bay.
You get to swim in it and it’s magical!

Cons

Much more out of the way if you are staying in San Juan. (It’s about 2 hours away from San Juan.)

Dark photo where you can vaguely see a shadow of someone in the water and blue glowing water immediately around them. — Moving quickly to make the water glow in La Parguera!

Best Time To See Bioluminescent Bays in Puerto Rico

The best time to see a bio bay in Puerto Rico is going to be as close to a new moon as possible. This is when the sky will be the darkest and your visibility will be best.

In fact, most of the tour companies in Puerto Rico do not offer tours on the days surrounding a full moon because the sky is too bright.

Tips for Your Bio Bay Tour

Here are a few tips to have the best time on your bio bay tour!

Be prepared to get wet! Definitely wear a swimsuit and be ready to get wet. In Laguna Grande, we had to wade in waist deep water to get to the kayaks, in La Parguera we swam, and even in Mosquito Bay we still got a little wet kayaking.
If the moon is out, put a shadow between it and the water. Moonlight (even the tiniest sliver) makes the bioluminescence harder to see. So if the moon is out, block the moon with your body and look at the water in the shadow to see it better.
Have fun with it! Bioluminescence is caused by the dinoflagellates reacting to motion. So stick your hands in the water and move them around! Make a fist in the water and then fling your fingers out! Splash water up onto your legs! Lift your hands out and watch them glow like there are stars in them!

Where To Stay Near Puerto Rico’s Bioluminescent Bays

Looking for a place to stay near Puerto Rico’s bio bays? Here are some recommendations!

Laguna Grande

We ADORED our stay at the Hyatt Regency Grand Reserve, which is about 45 minutes from Laguna Grande. (Read our full review here.)
El Conquistador Resort would be my choice next time and it’s JUST down the road from Laguna Grande.

Mosquito Bay

This is the vacation rental we stayed in with family on Vieques and we thought it was great!
Some other options that look great include Blue Horizon Boutique Resort, Finca Victoria, and The Vieques Guest House.

La Parguera

We stayed in Ponce at the Hilton Ponce Golf & Casino Resort. It was fine, but honestly very dated.
Next time I would probably stay at Parguera Plaza Hotel (where we actually had a great meal after our tour!). Although if you’re traveling with a family, this one is adults only.