Jellyfish on the NH Seacoast: What to Know Before You Paddleboard
For some, jellyfish spark a bit of fear—visions of stings and unexpected encounters in the water. For others, they’re a source of fascination: beautiful, alien-like creatures pulsing just below the surface. Whether you're curious or cautious, we’re here to share what makes jellyfish so unique, how to identify the two most common types you’ll spot while paddleboarding the New Hampshire Seacoast, and why a SUP tour with us might just be the perfect way to view them.
The Most Common Jellyfish on the NH Seacoast
While there are many jellyfish species in the ocean, the two you're most likely to encounter while out on a paddle are:
Lion’s Mane Jellyfish
Moon Jellyfish
Let’s dive in!
1. Lion’s Mane Jellyfish
The Lion’s Mane is the world’s largest jellyfish species—an impressive creature with tentacles that can trail over 100 feet in the deep ocean. Here on the NH Seacoast, they tend to be a bit smaller, with bells around 1–3 feet in diameter and tentacles that may reach up to 30 feet.
In 2024, a record-setting Lion’s Mane washed up in Maine with a 7-foot-wide bell—an incredible reminder of what’s out there just beneath the surface in the Gulf of Maine.
These tentacles aren’t just for show—they help the jellyfish catch small fish, plankton, crustaceans, and even other jellyfish. And if you're lucky enough to join one of our Moonrise Paddleboard Tours in Portsmouth NH, you might catch a glimpse of their bioluminescence, where they glow with their own light in dark water. It’s a truly magical sight from atop a paddle board.
What if You Get Stung by a Lion’s maine Jellyfish?
The good news: most stings from Lion’s Mane jellyfish are mild. Yes, they can be uncomfortable, but they’re often treatable with simple remedies like vinegar, salt water, and cold packs. Of course, those with allergies or sensitivities should seek medical attention just in case.
Don’t let the possibility of a sighting keep you onshore—seeing a Lion’s Mane from a paddleboard is safe, memorable, and completely awe-inspiring.
2. Moon Jellyfish
Smaller and gentler than the Lion’s Mane, Moon jellyfish are delicate, elegant drifters you’ll often see hovering near the surface. Their translucent, slightly opaque dome makes them easy to spot, especially thanks to the four circular structures inside—those are their reproductive organs.
Moon jellyfish are fascinating creatures. They feed using short tentacles and sticky mucus on the surface of their bell. Unlike many other marine animals, Moon jellies can thrive in low-oxygen environments, which is why you’ll often find them where freshwater meets seawater, common in areas like Great Bay, NH.
Are They Dangerous?
Not at all. Moon jellyfish can sting, but it’s typically harmless and barely noticeable to most people. In some cultures, they’re even considered a delicacy!
You’re very likely to spot a few of these peaceful floaters while you’re out paddling—just one more reason to slow down, look closely, and enjoy what’s beneath your board.
Join Us on the Water
Jellyfish might have a reputation that makes some nervous, but the truth is: they're mesmerizing, important parts of the marine ecosystem—and seeing them from the peaceful vantage point of a paddleboard is something special. Whether you're a marine life enthusiast or just love being on the water, a SUP tour with us offers a safe, front-row seat to the natural wonder of jellyfish on the NH Seacoast.
Book your paddleboard rental in Portsmouth NH or a guided SUP experience from New Castle NH today and come meet the locals—tentacles and all!