Nighttime in the Virgin Islands is often aglow with bioluminescence, but the conditions must align perfectly to witness one of nature’s most stunning light displays. Consider this article a how-to guide on swimming with the bioluminescence around St. John USVI.

Bioluminescent Beaches & Bays Around St. John, USVI

Though not as famous as Mosquito Bay in Puerto Rico (often called the brightest bioluminescent bay in the world), visitors to St. John or anywhere in the Virgin Islands can just as easily experience this underwater razzle dazzle. Some of the best bioluminescent beach locations include Hawksnest, Maho and Salt Pond.

When Should I go?

It’s easier to predict the Northern Lights (aurora borealis) than it is to guess when the water will be afire with gazillions of light emitting plankton. This is because factors such as water temperature, the amount of plankton present, and the cycle (and brightness) of the moon all play into whether visitors will encounter the mystical glowing blue waters of the Caribbean.

What Swimming In Bioluminescence Feels Like

When everything aligns it's pretty magical — like swimming in glitter. When you move it activates the light; like when you move your arm through the water you'll see all these tiny flecks of light.

Bioluminescence In The Virgin Islands Is Bright

It is definitely bright enough to notice, especially on new moons when the nights are the darkest. It also gets brighter when disturbed. For example, if you kick your feet really fast the little specks of light become bigger and brighter, or it can appear more luminous as it moves through a rolling wave.

Bioluminescence Tracker - New Moon Dates

As noted above, stumbling upon one of these glowing plankton beach zones is unpredictable, but if you want to improve your odds of being one of the few humans to see the ocean light up, then consider scheduling your trip to the Virgin Islands when there is a new moon.

Here is a list of upcoming new moon dates (pulled from sources like Mooninfo.org, so be sure to doublecheck the accuracy before booking):

July 24, 2025
August 23, 2025
September 21, 2025
October 21, 2025
November 20, 2025
December 19, 2025
January 18, 2026
February 17, 2026
March 18, 2026
April 17, 2026
May 16, 2026
June 14, 2026
July 14, 2026
August 12, 2026
September 10, 2026
October 10, 2026
November 9, 2026
December 8, 2026

No Need To Swim Out Far To See The Glow

You don't have to swim far out at all to be amid the bioluminescence. It can be experienced right off the shore in waist deep water. The best times to play in it are summer nights when there's no moon, the water is warm, and the sky is dark.

Bioluminescence Charter Trips In The Virgin Islands

While Island Roots Charters does not run night charters, there may be nighttime kayak tours that visitors can book and perhaps get lucky enough to paddle out into a fluorescent sea. These kinds of tours aren’t required though, as it’s just as easy to walk out to a beach on a dark night when these millions of microscopic phytoplankton ignite and jump right into a miniature underwater version of the ocean’s Milky Way.

Beyond Plankton, Other Life On Earth Also Glows

Bioluminescence doesn’t just occur in the Caribbean Sea in plankton dinoflagellates. Jellyfish and anglerfish can also emit natural light. On land, glowworms, fireflies, fungi and mushrooms, like the Jack O’Lantern, can glow in the dark. Foxfire or fairy fire refer to the dazzling special effects one might encounter as a result of nature’s custom-made LEDs that science more formally calls bioluminescence.

The color of the light that living organisms can emit ranges from blue and green (most common) to reds and violets (more rare). For example the deepsea loosejaw fish emits a red light that its prey and predators cannot see, serving as camouflage in self-defense and for hunting.

Bring Your Glowing Brains To The USVI

2025 research is finding that the human brain emits a glow too, albeit very faint, but it’s easy to imagine billions of neurons flickering within the dark caves of our skulls.

Bring your own glowing self down to the USVI, slip into our late night underwater disco party, and bob to the beats of the gentle waves filled with living lights.

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