Jellyfish in Washington: Identification Guide and Where to Start Looking

1. What Are the Key Identification Markers for Jellyfish in Washington?

Start with the bell. Moon jellyfish (Aurelia aurita) have a translucent, saucer-shaped bell with four horseshoe-shaped gonads visible through the top. Lion's mane jellyfish (Cyanea capillata) have a reddish-brown bell with a mass of long, thin tentacles that trail behind. Bell diameter ranges from a few inches to over 6 feet for lion's mane. Also note the number and thickness of tentacles: moon jellies have short, fine tentacles around the rim, while lion's mane has multiple long, hair-like tentacles.

See ourJellyfish guidefor the next step.

2. Where in Washington Do People Usually Spot Jellyfish First?

Most sightings occur along the outer coast, especially in places like Olympic National Park's beaches (Rialto, Second, and Ruby beaches) and the San Juan Islands. In Puget Sound, look for them in calm, protected bays like Hood Canal or near the ferry terminals. Jellyfish often drift near the surface after warm spells, so check areas with slow currents and minimal wave action. They also wash up in large numbers on coastal beaches after storms.

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3. When Is the Best Time of Year to See Jellyfish in Washington?

Peak jellyfish season runs from late spring through early fall, typically May to September. Warmer ocean temperatures and increased plankton blooms drive their numbers up. In Puget Sound, moon jellyfish are most abundant in summer months (July through September). Lion's mane jellyfish appear earlier, sometimes as soon as April, and can remain visible into October. Early morning or late afternoon offers the best odds for spotting them near the surface.

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4. What Are Common Lookalikes and How Do You Tell Them Apart?

The main lookalikes are ctenophores (comb jellies) and sea nettles. Comb jellies are transparent and have eight rows of cilia that shimmer iridescently, but they lack tentacles and can't sting. Sea nettles (Chrysaora fuscescens) have a golden-brown bell and long, stinging tentacles; they look similar to lion's mane but are smaller (up to 1 foot) and have a more bell-shaped bell. To separate moon jellyfish from a water jelly (Aequorea victoria), check for the four rings: moon jellies have distinct gonads, while water jellies have radial canals.

See ourstate animal guidefor the next step.

5. How Do You Safely Observe Jellyfish in the Wild?

Keep a safe distance, even with moon jellyfish, as they can still sting sensitive skin. Use binoculars or a camera with a zoom lens to examine details without touching. If you find a washed-up jellyfish, look for the telltale signs: collapsed bell, tentacles still visible, and a clear or purple tint. Wear shoes when walking on the beach to avoid stepping on hidden tentacles. The Washington Department of Fish and Wildlife advises not handling any jellyfish you can't identify.

6. What Equipment Helps with Jellyfish Identification?

A waterproof field guide or a phone with a waterproof case works well. A simple clear glass jar (used carefully) lets you examine a small specimen without touching it. For photography, a polarizing filter helps reduce surface glare. If you're serious about tracking sightings, keep a notebook or use a citizen science app like iNaturalist to log species. This gear is minimal, but even a good pair of polarized sunglasses improves visibility into the water.

7. How Can You Remember the Species You See?

After a day on the coast, you might want to note the key features: bell shape, color, tentacle structure, and location. For example, "moon jelly, translucent, four rings, seen at Rialto Beach in August." If you're looking for a way to carry that memory, consider aJellyfish Species Chart T-Shirtthat shows all the common Pacific species side by side. It makes a good reference when you're out in the field.

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Another option is theMoon Jellyfish Mugfor your morning coffee, with a scientifically accurate coral reef design that includes moon jellies.

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For a more general option, browse ourwildlife tote bagsto carry your field gear in style.

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8. What Should You Know About Stinging Species in Washington?

Lion's mane jellyfish can deliver a painful sting, though it's rarely life-threatening. Moon jellyfish stings are mild and often go unnoticed. Sea nettles, which appear less frequently, have a stronger sting. If stung, rinse with vinegar (not fresh water) to neutralize nematocysts, then remove tentacles with tweezers. Avoid rubbing the area. In Washington, jellyfish stings are most common in late summer when swimmers encounter drifting tentacles.

9. Are There Any Jellyfish Citizen Science Projects in Washington?

Yes. The Jellyfish Counter app and iNaturalist.org both accept sightings. The Olympic Coast National Marine Sanctuary also runs a jellyfish monitoring program. You can contribute your identification photos to help track seasonal patterns. This is a great way to turn your observation into useful data.

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