Blog posts
The Water Glows in Fajardo, Puerto Rico

The Water Glows in Fajardo, Puerto Rico


As it grew dark last night, our excitement grew over kayaking in the luminescent lagoon. Our tour guide picked us up around 6 and drove us to Las Cabezas in Fajardo.  I had booked a guided kayak tour of the Bio Bay or Bioluminescent Lagoon as it’s often referred to. The bioluminescent lagoon attracts lots of tourists by night who come in boats or kayaks to see the glowing water.

The Fajardo lagoon is one of three bioluminescent lagoons in the area.

BioBay Fajardo

Once we arrived, we were greeted by our guide Puerto Rico Eco Tours who went thru the safety rules and fitted us with lifejackets.

It was a windy night and the water was a  little choppy which concerned me.  I’ve kayak in the past but never done ocean kayaking before.  I get seasick very easy on boats when they start to rock.  Was I concerned? No, I was terrified. All the same, off we went. The guide put a fluorescent light in the front and the back of each of our kayaks.    My husband and me were in a double kayak and the three kids in a triple.  Our guide was in a single kayak.

We kayaked thru some of the boats that were off shore following the guide across a small basin towards a mangrove swamp.  It was pitch dark by the time we arrived at the mangroves.  All we could see was the fluorescent stick on the kayak in front of us.   The channel is narrow to begin with but there are also other boats to contend with.  Many groups go in at the same time, so some others were coming out as we entered.  So we were told: “Stay to the right of the channel at all times.”  So we needed to stay to the right of the oncoming boats,  keep a little distance from the kayaks in front of  us, and avoid the mangrove tree branches that we could hardly see.

At one point our guide turned on his flashlight headband for a minute to check on us.  I saw what looked like birds flying in front of me.  I immediately realized that those weren’t birds, they were BATS.  The guide told us that the mangroves had all kinds of animals on the branches.   As you paddle you hear the water splash not knowing if it’s a fish that jumped from the water or something that fell off a branch into the water.   After paddling for what seemed to be an hour we came out of the mangroves into a large lagoon, which resembled a large lake.  It was dark, quiet, and the water was calm.   You can see some of the city lights in the distance.   When we looked up into the sky it was full of stars.  We sat in the lagoon for about 10 minutes.    Watching kayaks in the distance coming and going from the mangroves.

Bio Bay Kayaking


The sky started to light up.  It looked like a thunderstorm was approaching so we started to head back into the mangroves.  Our guide had us stop and swish our arms and paddle around in the water.  The water started to sparkle like diamonds of light dancing around in the water.  When these million of tiny dinoflagellates microscopic organisms are agitated, these plantlike life-forms produce light and glow.   It was quite an experience to see.  We shortly paddled back thru the mangroves to the shore to meet our driver.   The excursion took around an hour and a half.

Bio Bay, Fajardo

Bio Tours

Swimming is not allowed anymore.   It’s again the law.  Certain chemicals that we apply to our skin like bug spray, sunscreen, lotions will harm the ecosystem and kill the organisms.  The most you are allowed to do is put your leg or arm into the water.   We used our paddle and our hand to stir up the water.

There are other bioluminescent bays around the island of Puerto Rico, they say Mosquito Bay on the Island of Vieques, is the most bioluminescent in the world.    It contains more than 160,000 microscopic dinoflagelates per liter of water.  It shines with the most intensity.

It was truly an adventure not to be missed if you’re visiting Puerto Rico. Make sure when you book our tour guide you ask about the size of the group.   We went for a private tour guide. Some of the other tour groups go out with parties of 15-30 people.  It’s hard to hear your guide when you have 20 people a head of you.  It can become quite crowded and you can bump into each other with so many kayaks in the water.

Bring a waterproof camera with you.   We didn’t bring our camera because we were worried that it was going to get wet.   Our guide took our pictures with his waterproof camera.   It’s hard to focus when it’s pitch dark.

Have any of you been to the Bio Bay?  How was your experience?

About the author

Carmen Edelson is the Founder of Carmen's Luxury Travel. Carmen has been traveling the world for over a decade. Her travels allow her the opportunity to pursue her itch to travel to the best luxury destinations, and experience those first class tastes from around the world.


  1. A Southern Gypsy
    December 30, 2013 at 12:36 pm

    I love this! I’ve heard about this in Puerto Rico and it’s been at the back of my mind to remember once I make it there. Thanks for linking up to the Sunday Traveler this week 🙂

  2. Carmen
    December 30, 2013 at 1:31 pm

    Thanks Ashley, It’s definitely a must see if you’re in Puerto Rico. I look forward to connection with others on the Sunday Traveler link up.

  3. Mrs. Chasing the Donkey
    January 3, 2014 at 3:03 pm

    Thanks so very much for linking up with us this week. I hope it’s okay, but I have also pinned this to my board as I am sure others would love to know about such a great spot.

    • Carmen
      January 4, 2014 at 5:09 pm

      Thanks for getting the word out and sharing my post. I greatly appreciate it.

  4. Stacey Veikalas
    January 26, 2014 at 1:54 pm

    WOW this place is really cool! I am going to have to add it to my list of places to go! It reminds me of the Blue Grotto in Italy ~ I wonder if it is the same reason it glows there! Thanks for Sharing! 🙂

    • Carmen
      January 26, 2014 at 6:11 pm

      I believe in Blue Grotto the water glows from the refraction of daylight through the above water cave opening. In Puerto Rico it’s caused by the tiny dinoflagellates that lit up like sparklers in the water with any movement. It’s pretty incredible to see.

  5. Melissa | Suitcase and Heels
    June 3, 2015 at 9:04 pm

    I did this last year and it was one of the coolest things I’ve ever done! Completely stunning. I did it in both Fajardo and Vieques. The only thing I didn’t like was the kayak through the mangroves to get to the lagoon in Fajardo. Talk about stressful when you lose your guide and don’t have a headlamp!

    • Carmen
      June 25, 2015 at 12:12 pm

      We didn’t like the kayaking in the dark through the mangroves either. It was an amazing experience.

  6. Brianna
    October 10, 2017 at 8:20 pm

    Man, I was supposed to go to Puerto Rico last month and I was going to do this. It’s still on my bucket list!

    • Carmen Edelson
      October 16, 2017 at 1:43 pm

      My heart is breaking for Puerto Rico.

Leave a Comment

Your email address will not be published.

CommentLuv badge

This site uses Akismet to reduce spam. Learn how your comment data is processed.