Bioluminescent Bay Puerto Rico| 3 Brightest Spots to See

One of the most stunning natural wonders of the Caribbean, when it comes to seeing bioluminescence, Puerto Rico has some of the best spots anywhere in the world for seeing this natural phenomenon. 

You may well have seen pictures of the bioluminescent bay, Puerto Rico, which glows at night and looks magical, thanks to rare and unique ecosystem conditions that cause the sparkling blue underwater light. In fact, there are 3 different spots where you can see the Puerto Rico glowing water around the island – each with their own pros and cons which I’ll cover in this guide.

If you’re looking for the best and brightest bio bay in Puerto Rico, Mosquito Bay on Vieques is the top pick. It’s recognized as the brightest in the world, so it’s definitely worth the extra trip over to Vieques. Not to mention, Vieques is an amazing island that you really should spend some time exploring!

If you’re hoping to see one of the bio bay, Puerto Rico locations during your trip here, keep reading – as I’ll take you through everything you need to know to choose which bioluminescent beach Puerto Rico is right for you and what you need to know before you go there. 

In This Post:

In this post I share my tips for choosing the best bioluminescent bay Puerto Rico tours as well as how to choose the best bioluminescent bay. Best time to go depends on many factors as well, which I’ll talk about below, too. 


Considering there are only 5 spots in the world where you can see bioluminescence year round, and Puerto Rico has 3 of them – there are fewer better places to take advantage of this beautiful phenomenon and plan a trip to see one of the bioluminescent bay PR sites. 

Puerto Rico Bio Bay Map- labels for La Parguera, Mosquito Bay, and Laguna Grande
Click map for more detailed view.

There are 3 different places where you can see the bioluminescence phenomenon in Puerto Rico. These are: 

  • Vieques (Mosquito Bay)
  • Laguna Grande, Fajardo
  • Lajas (La Parguera)

Which is the best phosphorescent bay Puerto Rico will depend on a few factors, such as where you’re based, how much time you have, how you want to see the Puerto Rico illuminating water and more. 

People kayaking in Bahia Bioluniniscente - Fajardo
Image courtesy of Discover Puerto Rico

If you’re looking for the bioluminescent bay San Juan, there isn’t bioluminescent water in the city itself, but Laguna Grande, Fajardo is only a short distance away and is therefore one of the most visited spots. It’s sometimes referred to as the “Puerto Rico glowing lake” thanks to its lagoon-like shape. Bio bay Fajardo is a popular day trip from San Juan

If you want to visit the very best bioluminescent bay Puerto Rico has, then I suggest planning to visit Mosquito Bay, which has the brightest bioluminescence of the 3 and is a more tranquil spot, perfect for nature lovers. Located on the island of Vieques, the Vieques bioluminescent bay is located to the south east of the main island of Puerto Rico. Vieques island is a paradise for those who are looking for eco adventures, as you’re on the edge of the Vieques national park which covers over half of the island. Mosquito bay is the glowing beach Puerto Rico you may well have seen photographed. 

Read More: Best Beaches on Vieques

La Parguera bioluminescent bay is located in Lajas at the southwestern end of Puerto Rico is the least visited fluorescent water Puerto Rico spot, and it’s also the least bright. It’s the only spot where motor boats are allowed, so if you’re looking for a tour that doesn’t involve kayaking, this might be the best bet for you. 


If you haven’t come across a bio bay before, the scientific phenomenon that creates the “glow in the dark” beach Puerto Rico and all of the best bioluminescent bay Puerto Rico places is pretty fascinating! 

The bioluminescence (also sometimes just called luminescence) is created thanks to the presence of Pyrodinium Bahamense in the water, which is a single-celled organism. It’s a type of dinoflagellate and phytoplankton, which, when agitated, produces bioluminescence which looks like blue light. 

hand in bioluminescent water
Image courtesy of Discover Puerto Rico

Bioluminescence is simply defined as the production and emission of light by a living organism. It occurs when there are enough dinoflagellates present in one concentrated area, and the organisms are disturbed by movement (such as paddling). Interestingly, the number of dinoflagellates – which are rarely found in a high enough concentration to create bioluminescence in other parts of the world – has actually increased since hurricane Maria in some places. 

The bioluminescence at Mosquito Bay, Vieques, has also received an unintentional helping hand along the way! The story goes that the Spanish colonists, who settled in this part of the Caribbean, thought that the bioluminescence was the ‘work of the devil’. In attempting to prevent the bioluminescence from spreading inland via rivers, the stones that they put around the bay have helped to maintain the number of dinoflagellates in the bay, the result being the most beautiful fluorescent bay Puerto Rico has. 


The best time to see the Puerto Rico glow in the dark water depends on a couple of different factors. 

Firstly, you’ll want to check the lunar cycle. At any of the bio luminous bay Puerto Rico options, you’ll see more bioluminescence the darker the sky is. So for that reason you’ll get best results around the new moon – when there’s less light in the sky – and be able to see less around the full moon. Try to avoid visiting around the full moon if you can, however if skies are cloudy, it matters a little less than if they are clear. If you’re not sure what phase the moon is in, there are plenty of websites you can check the current lunar cycle on. 

Secondly, it’s better to visit when the waters are calm, especially for some of the glowing bay Puerto Rico options. La Parguera bio bay is much more exposed than the others and can get more rough in higher winds, such as during the hurricane season, making it unsuitable for kayaking. 

Also do call ahead before your trip to any of the luminous bay Puerto Rico sites to check on the condition of the dinoflagellates, which are monitored. 30% is around the minimum level where they are visible in the water, but for a more impressive experience you’ll want higher. If you’re going with any of the Puerto Rico bio bay tours, chances are they won’t take you out if conditions are bad, but I still recommend phoning ahead to check. 


If you’re wondering what the best way to see the luminescent water, Puerto Rico is, there are a few different options to consider. 

The most common way to explore the bio bays is to take one of the bioluminescent tour Puerto Rico options – and there are many companies offering different or similar tours. 

Bioluminescent Bay Puerto Rico Tours

Taking a tour is the most common way to see the bio bays, and there are several different options depending on whether you’re looking for bioluminescent bay Puerto Rico boat tours, a San Juan bioluminescent bay tour, or a night kayaking Puerto Rico tour. 

You can either reach the bay by yourself and then find a tour operator in the location of your bio bay to take you out by kayaking, or you can choose one of the San Juan bioluminescent tour options which includes transport to the bio bay. 

Almost all tours are by kayak, which allows you to paddle out from the starting point to explore the bio bay, and there are also some tour options which include transport to/from San Juan and other parts of Puerto Rico to your chosen bio bay area. 

Whichever option you decide to go for, do read reviews for your chosen operator ahead of time. Prices vary depending on the operator and what’s included. 

Bioluminescent Kayaking Puerto Rico

Regardless of which type of tour you choose, you’ll likely end up on a Puerto Rico kayak bioluminescent tour when it comes to exploring the bio bays themselves, but there are a few electric powered boat tour options is you prefer that.  

kayakers in bioluminescent water at La Parguera
Image courtesy of Discover Puerto Rico

Kayaking tour packages either depart around sunset – which has the advantage of being able to watch the sun go down as you kayak out to the bay, or if you want total darkness to enjoy the bioluminescence at its best, I recommend taking the second tour timing option which leaves at around 7.30 or 8.00 in the evening. 

Whether you’re looking for a Fajardo bio bay kayak tour, a tour with Vieques kayaks bio bay, or want to go La Parguera bio bay kayaking there are plenty of options to choose from. 

Can I go on my own?

Although it is possible to go on your own to any of the bio bays in Puerto Rico, it’s not logistically very practical to visit the luminescent water Puerto Rico has by yourself – unless you have your own kayak and transportation for your kayak. 

If you are a local and have your own kayak, then it’s possible to kayak out to any of the bio bays, but you need to know what you’re doing in the dark and be confident in the waters – so I don’t recommend it unless you are an advanced kayaker and know the waters around Puerto Rico well. 

For this reason, almost all visitors to Puerto Rico take a tour to see the bioluminescent lagoon Puerto Rico or any of the other bio bay sites. 

Can I swim?

Another common question I hear is – is it possible to swim in bioluminescent bay Puerto Rico? The answer is no – swimming is not allowed, and the main reason is to protect the dinoflagellates from damage. 

The dinoflagellates are sensitive and are killed off by the chemicals found in bug spray and sunscreen, which is why the no-swimming rule. Technically speaking, swimming itself does not cause harm, but the chemicals found in lotions and creams on human skin do. 

One exception to this is if you visit La Parguera bioluminescent bay, where swimming is allowed as this is open water rather than a bay or lagoon, strictly speaking. This spot is also less popular and well known, partly as the brightness of the bioluminescence is less here.  

Vieques Bio Bay Tours

The bio bay in Vieques is our favorite in Puerto Rico. Vieques is one of our favorite islands in the entire Caribbean because of it’s incredible and secluded beaches, good snorkeling, and laid back vibe. Plan time into your trip for Vieques and you won’t regret it! We love it so much, it’s where we spent our honeymoon.

If you want to take a Vieques bio bay tour, there aren’t many Mosquito bay tours from San Juan, so you’ll need to travel to Vieques independently and take one of the Vieques kayaks tour options from Mosquito bay. 

Several of the tour options on Vieques offer pickup from either the ferry port or the airport, but they will require an overnight on Vieques. Spending the night on Vieques is really the only way to take in a night bio bay kayak tour from Vieques. 

If you’re short on time, fly directly from San Juan to Vieques for the Vieques bio bay tour. We’ve flown and taken the ferry both and would definitely recommend flying. The flight is less stress and offers beautiful views along the way. However, if you find you have more time and don’t want to spend the money on a flight, the ferry is another good option to get from Ceiba to Vieques and then start your Vieques bioluminescent bay tour. 

In order to find the best bio bay tour Vieques has, I recommend shopping around and comparing a few prices, options and reviews first. In addition to the regular kayaks, the Vieques bio bay tour clear kayak option makes for an extra special experience and is worth a try. 

Read tour reviews on Trip Advisor HERE.

Check out tour options through Viator HERE and Get Your Guide HERE.

Fajardo Bio Bay Tours

The most popular spot for seeing bioluminescence, PR,  thanks to its location closer to San Juan, is the bioluminescent bay Fajardo. 

Located on the east coast of Puerto Rico outside the town of Fajardo, Laguna Grande Fajardo is the only bio-bay that’s not actually a bay. Instead it’s a lake or lagoon, that can easily be explored by kayak at night to see the beautiful bioluminescence. Although it’s not quite as bright as the bioluminescence Vieques has here, this bioluminescent lake, Puerto Rico, is still a great experience.  

If you take a San Juan bioluminescence tour, chances are you’ll come here to see the bioluminescent Fajardo has. There are plenty of different minivan tours from San Juan that will take you to Fajardo in time for your evening kayak Fajardo tour, and there are other Fajardo bio bay tour companies that offer free pick up from many parts of San Juan. 

One of our top picks for Fajardo bioluminescent tour options is one that combines el Yunque rainforest trekking in the day time with kayaking the bio bay at night. 

Read tour reviews on Trip Advisor HERE.

Check out tour options through Viator HERE and Get Your Guide HERE.

La Parguera Tours

Last but not least, La Parguera Puerto Rico bioluminescent bay is a good spot for those who want to avoid any crowds and have a more ‘local’ Puerto Rico light up water experience. 

Located in Lajas, on the south-western corner of Puerto Rico, La Parguera is a beautiful nature reserve that holds plenty of opportunities for underwater exploration, boat trips to different cays, snorkeling and diving. 

If you choose a La Parguera bio bay tour over one of the other bio bays, the advantage is you may be able to swim here (check with your operator and avoid wearing any chemical sunscreen or bug repellant). 

There are La Parguera bioluminescent bay tour options from San Juan, but with a longer drive than to Fajardo. Expect it to be around 2 hours each way from Lajas to San Juan if you just come to this part of the island for a bio bay tour. Mini vans will organise pick up from SJ or other parts of the island and transport your shared or private group before heading out to the Lajas bioluminescent bay. 

Here you can often choose between heading out on a motor boat and then swimming, or choosing a regular or clear bottom kayak tour. 

Read tour reviews on Trip Advisor HERE.

Check out tour options through Viator HERE and Get Your Guide HERE.


Before heading out on any of the bio bay tours Puerto Rico has, here are a few handy things to know before you go. 

Bio Bay PR: Know before you go

bioluminescence in water


Unfortunately hurricanes can have a devastating effect not just on the people living in Puerto Rico and the rest of the caribbean, but they can also significantly damage and alter onland and underwater ecosystems as well. 

Hurricane Maria hit Puerto Rico especially hard in 2018, and caused much damage. Some of the mangroves surrounding the bio bays were damaged, especially the bioluminescent Mosquito Bay, Puerto Rico, where on the other hand the bio bay Parguera saw hardly any impact. 

Since then, the ecosystems are recovering, and hurricanes can also have a positive influence on the number of dinoflagellates in the water. If you’re concerned about hurricane damage and impact on the bio bays before your trip, the best thing to do is ask local people for up to date info once you’re in Puerto Rico. 


Unfortunately, beautiful as the photos you’ll see online when you google things like “Puerto Rico light up beach” or “Puerto Rico beach that glows at night” are, do know that your experience will not really look like that and that those pictures are all heavily edited. 

It’s practically impossible to capture the actual conditions and experience of the luminescence as it’s not the actual water that glows blue, but rather the flagellates in it when disturbed by movement. Nearly all of the pictures you’ll see online have been photoshopped to promote the experience. When you first see the water at night, you might not notice anything – but once you start paddling through it, you’ll start to see the blue, depending on the conditions of the water. 

Most of the bio bay tour companies recommend leaving your camera in your hotel to avoid any risk of it getting wet. 


Mosquito bay on Vieques is not named after everyone’s least-favorite buzzing friend for nothing! If you’re heading out kayaking to any of the bio bays – and especially on one of the sunset tours – make sure you prepare to avoid them by covering up your arms and legs and wearing mosquito repellant. 

Since mosquito repellant damages the dinoflagellates, wear natural repellant wherever you can, even if you’re not swimming. Small amounts of chemicals from hands in the water can still cause a problem. 

Help Maintain the Eco System

The bio bays are a delicate ecosystem and a world-treasure, and travelers can help keep them that way. 

Some of the most important things you can do to help protect this beautiful phenomenon include: 

  • Go with a licenced tour company – not only will you be going someone who knows all about the luminescence and can keep you safe, but you’ll also be supporting the local economy
  • Do not swim in the bio bays (unless you are told you are allowed to at bio bay Parguera). Do not get in the water anywhere if you are wearing any lotions or repellant on your skin. 
  • Choose quieter bays to visit to avoid overcrowding, or visit at less busy times of the year outside peak season
  • Avoid use of single-use plastic while on these tours as waste facilities can be lacking and plastic often ends up in the water. 
  • If you happen to be in PR during a full moon, some companies offer full moon tours to take in the beautiful moonlit mangroves instead, when it’s much less busy too! 


Still not quite sure which is the best phosphorus bay Puerto Rico has for you? For most people it comes down to time and distance from where you plan to spend the rest of your Puerto Rico vacation. 

Bahia bioluminescent Puerto Rico (Mosquito Bay on Vieques) is the best in terms of the brightness of bioluminescence but it is the furthest away San Juan – you’ll need a bit of time to get here so it’s best if you want to combine it with other things to do on Vieques. It can also get busy here, but if you do come here, you won’t be disappointed. 

If you want to stay on the main island of Puerto Rico, then you have the choice of either a Fajardo bio bay boat tour on the Laguna Grande, or visiting Lajas bioluminescent bay. Fajardo wins for convenience, ease, a shorter drive and brighter bioluminescence however do expect more crowds here. 

La Parguera glowing bioluminescent bay is much less popular, and for that reason may be the perfect option for some travelers. Although the bioluminescence is less bright here and it’s a longer drive from San Juan, the area here is stunning and you may have the chance to swim in the water with the bioluminescence – which can be a truly incredible experience. 

Whichever option you go for, most people love this experience in Puerto Rico.

Looking for more ideas for your next Puerto Rico trip??? Check out all of our Puerto Rico Guides HERE!

About the author
Kristin Young