Glowing Reviews: Bioluminescent Bays To Twinkling Caves

Bioluminescence does not require any source of external light, like the sun or a flashlight. Many of us first experience this delight from fireflies during the few weeks of mid-summer evenings. And as we travel the world, many of us have discovered that this production and emission of light by a living organism is among the loveliest wonders of them all.

The glow can come from worms, in dark caves, such as in Dismals Canyon in Alabama, with hundreds of tiny bioluminescent gnat larva. known as “Dismalites.” They are found in only a few places on Earth, related to the bioluminescent fungus gnats found in caves in Australia and New Zealand.

Perhaps most spectacular is the glow that comes from creatures in the water, sometimes called ‘sea fireflies.’ Scientists say the twinkling blue is caused by light-emitting microorganisms, including bacteria, living near the surface — nocturnal scavengers that use their light displays for defense and in courtship. Bioluminescent creatures, including phytoplakton, squid, shrimp, and some fish are found throughout marine habitats, from the ocean surface to the deep sea floor.

Today, the glimmering power of bioluminescence has been harnessed for lifesaving uses in medicine, from lighting up structures inside the brain to illuminating the progression of cancer cells. But for travelers, it’s the beauty.

Bioluminescent bays are found all over the world, from the Maldives to Japan, viewed best from a dark beach at least two hours after sunset, during the new moon phase when the sky is at its darkest.

While the bio bays have some bioluminescence year-round, the best time to visit is during the dry season, as heavy rainfall can cloud the water and make it harder to see the glow. But be aware: Bioluminescent algae that twinkle along the seascape can poison sea life from fish to sea turtles, so swimming is not advised.

I remember the island coast of Vieques, outside Puerto Rico on a moonless night. The stars seemed to twinkle both above and in the wake along my boat. It seemed magical.

And more and more travelers are noting the beauty. “This rare natural phenomenon has captured the attention of millions and has taken over social media—with videos under the hashtag #bioluminescence on TikTok and over 100,000 photos under the hashtag on Instagram,” says Naveen Dittakavi, founder and CEO of Next Vacay. “Searches for ‘how to see bioluminescence’ have increased by 400% in the past year.”

Travel experts at Next Vacay reveal the top beaches, bays and caves that glow, judged by Instragram photos for the most popular spots. Here are the top four of them.

#1 Halong Bay, Vietnam

Halong Bay takes the number one spot as the world’s most glowing beach to witness bioluminescence, with over a million photos under the hashtag on Instagram.

Halong Bay has plenty more to explore, from the caves to the wilderness to the limestone islands. But its dazzling underwater light show is especially spectacular. At night, boat tours take people out on the water to see the fluorescent plankton.

#2 Mission Bay, San Diego, USA

Glowing neon-blue lights the water, and bioluminescent waves can sometimes be seen along the entire California coast. The dazzling display is in sync with what scientists call a “red tide,” a build-up of tiny organisms called dinoflagelattes, a common member of the Southern California plankton family with a reddish-brown color. When it accumulates significantly — sometimes called a “bloom,” the water can take on a red tint on sunny days.

#3 Isla Holbox, Mexico

This quiet Caribbean seaside destination on the north coast of the Yucatán Peninsula boasts an impressive volume of bioluminescent microorganisms.

#4 Titusville, Florida, US

With one of the most biodiverse ecosystems in the northern hemisphere, Titusville ranks fourth as the most popular destination in the world photographed to see bioluminescent waters. You can take a kayaking tour, and with each paddle in the glowing waters, stir glowing creatures swimming underneath.

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If you can’t get to bioluminescent waters at night, perhaps the rare fluorescent effect delights of sunlight shining through a narrow entrance will do. The Blue Grotto on the island of Capri, in Italy; and the nearby Green Grotto on the Amalfi Coast, are other popular spots. Be sure that the sun is in in the correct position to illuminate the water.

#5 Blue Grotto, Malta

The Blue Grotto in Malta is a sea cavern with unique limestone formations and views of water, flora, and fauna delivers a high dose of blue. Tourists embark on a boat ride to enjoy the glowing water views.

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Here are the remaining 15 glowing wonders throughout the world — including name, and Instagram hashtag. If you can’t visit in person, you can at least enjoy the photos.

6- San Juan Island, Washington, USA; #SanJuanIsland

7- Ton Sai, Krabi, Thailand; #TonSai

8- Little Corn Island, Nicaragua; #LittleCornIsland

9- Torrey Pines Beach, San Diego, CA; #TorreyPinesBeach

10- Waitomo Caves, New Zealand; #WaitomoCaves

11- Big South Fork, TN/KY, USA; #BigSouthFork

12- Luminous Lagoon, Jamaica; #LuminousLagoon

13- Reethi Beach, Maldives; #ReethiBeach

14- Toyama Bay, Japan; #ToyamaBay

15- Mosquito Bay, Puerto Rico; #MosquitoBay

(For more travel info and insights, follow my award-winning travel podcast, Places I Remember with Lea Lane. Listen on Apple, Spotify, or wherever you get your podcasts.)