You do not need a submarine. Some of the most spectacular bioluminescence on Earth can be seen from a kayak, a boardwalk or a forest trail.
Visitor information was checked in October 2026. Conditions, seasons, rules, prices and tour availability change – check with the local park, tourism board or tour operator before you go.
Glowing water
Mosquito Bay
Where
Vieques, Puerto Rico
What glows
Dinoflagellates
Best time
Year-round, on dark nights near the new moon – but see the October 2026 status note
Often called the brightest bioluminescent bay in the world, and recognized as such by Guinness World Records in 2006. Tours go out by kayak only, and swimming is not allowed, to protect the bay.
Status as of October 2026: the bay's glow has been much weaker than normal since a drought in July 2026, and Puerto Rico's Department of Natural and Environmental Resources (DNER) is studying the decline. Past dimming events have recovered within about one to eight months. Check with tour operators before you go.
Laguna Grande and La Parguera
Where
Fajardo and Lajas, Puerto Rico
What glows
Dinoflagellates
Best time
Year-round, darkest nights
Together with Mosquito Bay, these make Puerto Rico home to three of the best-known bioluminescent bays anywhere. Laguna Grande, near San Juan, is reached by kayak through a long, narrow canal. La Parguera is the only one of the three that allows motorboats, and it is the only one where some tours allow swimming – check the current rules with your operator.
Luminous Lagoon
Where
Falmouth, Jamaica
What glows
Dinoflagellates
Best time
Year-round, after dark
Nightly boat tours take visitors out on this lagoon, which glows when boats move through it or visitors trail a hand in the water. Swimming is allowed on some tours.
Toyama Bay
Where
Toyama Prefecture, Japan
What glows
Firefly squid (Watasenia scintillans)
Best time
About April to May (sightseeing-boat season)
Each spring, huge numbers of firefly squid rise toward the surface to spawn, lighting the bay in blue. Early-morning sightseeing boats from Namerikawa go out to watch in season, and the firefly squid's gathering area in the bay is protected as a Japanese Special Natural Monument.
Beaches of the Maldives
Where
Many islands, Maldives
What glows
Plankton in the surf
Best time
Unpredictable – depends on plankton blooms
On the right night, the surf glows blue along the shore, an effect nicknamed the "sea of stars". It can appear on many islands, not just famous ones, and it depends on plankton, so it is never guaranteed.
Indian River Lagoon
Where
Space Coast, Florida, USA
What glows
Dinoflagellates and comb jellies
Best time
Late May or June to October, peaking July to September, on dark nights
Guided night kayak tours paddle through water that sparkles with every stroke.
Glowing caves, forests and fields
Waitomo Glowworm Caves
Where
North Island, New Zealand
What glows
Glowworms (Arachnocampa luminosa)
Best time
Year-round
Guided tours finish with a quiet boat ride under a cave ceiling covered in thousands of tiny blue-green lights. Photography is not permitted in the Glowworm Cave. The cave has about 100 stairs and is not wheelchair accessible; the nearby Ruakuri Cave is wheelchair-friendly.
Great Smoky Mountains National Park
Where
Elkmont area, Tennessee, USA
What glows
Synchronous fireflies (Photinus carolinus)
Best time
Usually late May to early June (2026 event: May 20 to 27)
Thousands of males flash together in waves, then go dark at the same time. The event is so popular that the park runs a lottery for vehicle passes to Elkmont on Recreation.gov. In 2026 it cost $1 to apply and $29 if selected, and the application window was in late April. Next year's dates are usually announced in spring – check nps.gov before you go.
Congaree National Park
Where
South Carolina, USA
What glows
Synchronous fireflies (Photuris frontalis)
Best time
Usually mid to late May (2026 event: May 13 to 20)
Another US national park with fireflies that flash in rhythm, here in a floodplain forest. In 2026 the park used a lottery for parking passes ($25, 145 passes per night), and only red lights were allowed. Dates and rules change each year – check nps.gov before you go.
Dark, damp forests near you
Where
Many temperate and tropical regions
What glows
Foxfire and glowing mushrooms
Best time
Warm, wet nights; often summer and autumn
Look for rotting logs and fallen branches on a moonless night after rain. Switch off your light and give your eyes time to adjust before giving up.
Responsible viewing tips
Bioluminescent places are fragile. A few simple habits help keep them glowing for the next visitor.
Go dark. Plan around the new moon, and stay away from street lights and phone screens. Give your eyes plenty of time – many minutes – to adjust to the dark.
Skip the flash. Flash photography and bright lights disturb fireflies and glowworms. If you need a light, use a dim red one and point it at the ground.
Stay on the trail. Many fireflies rest and lay eggs in the grass and leaf litter at your feet.
Keep sunscreen and bug spray out of the water. Puerto Rico's tourism board advises not using bug spray or sunscreen before a bio bay tour. Where swimming is not allowed, do not swim.
Choose licensed, low-impact tours. Certified eco-tour operators know the local rules and how to protect the water.
Leave it as you found it. Do not collect fireflies, mushrooms or water samples from protected areas.