Diving With the Giant Pacific Octopus: What Cold Water Divers See That Warm Water Divers Don't
Christie Davis Oct 08, 2026
Happy World Octopus Day.
Most people picture scuba diving as warm water, bright reef fish, and a tropical beach. But the biggest octopus on the planet doesn't live there. It lives in cold, green Pacific water. Our water.
If you've ever wondered why anyone would suit up for a cold dive, this is one of the best answers we've got.
Meet the biggest octopus on Earth
The giant Pacific octopus is the largest octopus species in the world, and its range runs along the Pacific coast of North America all the way across to Korea.
Most weigh less than 70 pounds, but they can stretch 15 feet from arm tip to arm tip. The biggest one ever confirmed weighed 437 pounds.
They don't live long, though. Three to five years is about it.
You don't need a plane ticket. You need a good drysuit.
This is a cold-water animal. The best way to see one is to dive the cold water where it already lives.
That's the part warm water divers miss. No reef trip gets you this. It's one of the real perks of diving the Pacific Northwest.
How to actually spot one
They're hard to find if you don't know what to look for. An octopus can change color to match the rocks, and it spends the day tucked away. According to the Point Defiance Zoo & Aquarium, it rests in a den by day and comes out at night to feed.
So you're not looking for an octopus. You're looking for clues.
- Rocky crevices and holes. Dens are usually tucked into rocks.
- A pile of shells at the entrance. The octopus brings its meal home to eat, then leaves the leftovers by the door. Crab and clam shells outside a hole are a great sign, as noted by Animal Diversity Web and the SeaDoc Society.
- An arm that doesn't look like a rock. Slow down and look closely. Sometimes the first thing you see is just one arm.
Go slow. Bring a good light. Give your eyes time to adjust.
Look, don't touch
Giant Pacific octopuses are shy around people. The Animal Diversity Web describes them as timid and rarely aggressive unless challenged.
But they're not toys. The SeaDoc Society says diver attacks have been recorded, usually when the octopus was provoked, sometimes by someone trying to get a closer video. They can also deliver venom through a bite.
Here's the simple rulebook:
- Keep your hands to yourself.
- Don't block the den entrance.
- Don't chase it or poke at it for a photo.
- Keep your light off its face.
- If it pulls back, give it space and move on.
Divers in Washington have cared about this enough to change the rules. In 2013, after a public outcry over a legal octopus harvest at a popular dive site, the state banned recreational octopus harvest at seven dive sites. The state said octopuses are one of the main attractions for divers there.
Rules on taking octopus differ by place, so check your local regulations. Our rule is simpler: if you find one, enjoy the view and leave it where it is.
A short life with a big last chapter
Here's the part that makes people go quiet.
After mating, a female lays thousands of eggs on the roof of her den. According to Point Defiance Zoo & Aquarium, she guards them for months without eating. She only lays eggs once, and she dies soon after.
So if you ever find a den with a female tending her eggs, give her extra room. She's doing the most important job of her life.
Want to see one yourself?
Cold water diving is very doable with the right training and the right gear. We're a NAUI Pro-Platinum training facility right here in Astoria, and we can get you started.
- New to diving? Look at our certification courses to get your Open Water card.
- Already certified but new to cold water? Ask us about drysuit training.
- Not sure what to wear? Stop in the shop and we'll sort out your gear.
Come say hi, and tell us your best octopus story. We'd love to hear it.
