Seaside Safari

Exploring the Tide Pools in Seattle Southside

What to know and where to go

When the tide is low, a world of miniature marine life is revealed.

Searching for tiny critters on the beach is a classic local tradition. And as far as free, family-friendly activities go, it’s hard to beat. You might see bright, colorful sea stars, crawling crabs, jittery little fish, or even a small octopus. Here’s what to know before going tide pooling in Seattle Southside.

Where to Go
When to Go
Guidelines

Where to Go Tidepooling Near Seattle

Seattle Southside has several under-the-radar beaches perfect for tidepooling, including Redondo Beach (home of the MaST Center Aquarium), Des Moines Beach Park, and Saltwater State Park. Enjoy sweeping views of the sea and the Olympic Mountains, fewer crowds, and plenty of parking. All of these spots are a short drive from SEA airport and easily accessible from Seattle proper. (Note: a Discover Pass is required for parking at Saltwater State Park).

Redondo Beach

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Détails

Parc d'État de Saltwater

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Détails

When to Go Tidepooling

You'll want to go when the tide is low and more of the beach is exposed. You can use the Washington Department of Fish & Wildlife's tide chart to find a good time. Look for a negative tide (the lower the number, the better). Other resources include the MyCoast App, which users regularly update, and the NOAA Tides & Currents website. If you can, arrive at the beach about an hour before the tide is at its lowest, and plan to stay a couple of hours. That will give you ample time to explore before the tide comes in again.

Pro Tip: In 2025, some of the lowest tides occur on May 27 and 28 and June 23-28.

Want Expert Guidance?

Friends of Saltwater State Park Naturalists will be on the beach at Saltwater State Park for two-hour windows on select dates. Look for folks in reflective vests, and feel free to ask them questions about the beach and the marine environment! Check the organization's website and Facebook page for updates about when they'll be there. The MaST Center Aquarium also hosts Low-Tide Walks at Redondo Beach on select dates when the tide is below -1. Check the website and Facebook page for updates.

Respect the T.I.D.E.S.

The intertidal zone is full of fragile creatures. Aeriel Wauhob, Community Engagement Coordinator at the MaST Center Aquarium, came up with the acronym T.I.D.E.S. to guide explorers:

T - Tread lightly. There could be animals hiding on the algae or under the algae.
I - Investigate carefully. You can lift rocks to look for creatures, but do so gently and always put them back where they were. "We're the giants," says Wauhob. "We're basically taking the roof off their home."
D - Discover it, then leave it behind. It's tempting to take home a pretty shell or rock, but those could be homes for animals.
E - Educate others. Every beach has regulations, so look them up beforehand and inform others.
S - Stay aware of the tide at all times. You’ll want to know when it will come in again and have an exit route when it does.

What You’ll See

It helps to know what you're looking for on the beach, as some of the critters are very small (or very sneaky). To get an expert's perspective, we took a low-tide walk at Redondo Beach with Wauhob. It was late April, with a great low tide. Read on to find out which critters we saw—there's a good chance you'll see them, too!

Sea Stars

If you're lucky, you could see dozens of sea stars on the beach. These vibrant, puffy animals love to cling to docks—we spotted a bunch of eggplant colored ochre sea stars under the MaST Center. They can grow larger than an outstretched hand, though we also spotted some tiny orange babies on one of the dock's posts! Both ochre sea and mottled stars come in a range of colors, including orange, brown, and purple. You can tell them apart by their spiny patterns: ochre sea stars have a star-shaped pattern, while mottled stars have more slender arms and a more scattered, uneven pattern of spines. It’s okay to gently touch their rough, spiky skin. And don’t worry about them being out of water–they’ve evolved to be okay out of water at low tide.

Pictured: Ochre sea stars under the MaST Center Aquarium at Redondo Beach in Des Moines, Washington.

Moon Snails

When moon snails expand, they can be as large as a dinner plate! If you wade into shallow water, you might spot one of them, though it’ll likely be curled up in its shell. On shore, you can also find their black, circular casings or “sand collars” (named because they resemble the collar of a shirt). Each one contains around half a million microscopic snail eggs, which will eventually hatch in the water. In the spring, you can see hundreds of these collars on the beaches. Go ahead and touch one—they’re strangely and surprisingly smooth, almost like plastic!

Pictured: A moon snail shell found at Redondo Beach in Des Moines, Washington.

Clams

As you walk, you might notice little jets of water shooting up from the beach. That would be the gaper clams burrowed under the rocks in the intertidal zone. They shoot water out of their siphons when disturbed. So, watch out! And don’t lean down to peer at them unless you want a salty face wash. If something bright purple catches your eye, that also might be the broken shells of purple varnish clams.

Fun fact: A singular clam filters 50 gallons of water through its body every day!

Note: These clams are not suitable for eating.

Pictured: A gaper clam shell

Crabs

We share our shores with many types of crabs, including red rock crabs with large pinchers and northern kelp crabs, also known as shield-backed crabs because their backs resemble police badges or shields, both of which we saw hiding out in the kelp and under rocks. Our favorite sighting, however, was a decorator crab. These inventive creatures adorn their bodies with plants and even small animals to camouflage themselves and ward off predators. Diva alert!

Pictured: A red rock crab at Redondo Beach in Des Moines, WA.

Rarer Finds

These critters are more for advanced tide pooling...but that doesn't mean you need to be an expert. Just that you may need to be willing to wade into the sea a few feet and look very carefully below you.

Octopuses

Our most exciting find of the day was an eight-legged one! Our region is known for our red octopuses, which only grow to about 12 inches at their biggest but are still fascinating sights. These smaller cousins of the Giant Pacific Octopus come into the intertidal zone to hunt and hide under rocks during low tide.

Pictured: A small red octopus spotted at the water's edge at Redondo Beach in Des Moines, WA.

Sea Cucumbers

You'll likely have to wade into the water to spot a California sea cucumber, but if you're near one, you'll have no trouble identifying it. These slimy, spiny creatures look like nothing else. They can be red or yellowish, and grow over a foot long. Wauhob saw one while walking a few yards into the ocean. As an expert, she was comfortable putting them in a tub, as you can see in this photo, but we amateurs should avoid touching or moving them.

Fun fact: Sea cucumbers are great recyclers. They eat dead organic matter and expel clean sand.

Pictured: California sea cucumbers placed in a tub by a staffmember at the Mast Center Aquarium in Des Moines, Washington. (While researchers can safely handle them, avoid picking one up yourself!)

Planning Checklist

  • Check the tide chart.
  • Wear rain boots or closed-toe sandals that you don't mind getting wet and dirty.
  • Pack some sun protection like a hat, sunglasses, and sunscreen.
  • Leave dogs at home, as they can be disruptive and harmful to wildlife.
  • Don't bring a bucket; one of the golden rules of tide pooling is to leave or return everything to where you found it.

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Annie Atherton

Auteur

Annie Atherton

Rédacteur principal de contenu

Annie Atherton est rédactrice principale à Explore Seattle Southside. Résidente de la région de Seattle depuis (presque) toujours, elle est très fière d'y habiter et d'en parler à tous ceux qui veulent bien l'entendre.