Arachne Reef - Pacific Northwest
Arachne Reef. We’ve had some truly fantastic dives here, and we'd argue it’s one of the most underrated spots in the PNW. Forget the big, famous wrecks for a minute; this reef offers a different kind of magic. Dropping down, you’re often greeted by dense schools of pacific sardines, flashing silver as they swirl past. It’s not uncommon to see a spiny dogfish cruising through them, sleek and purposeful. The visibility can swing a bit, but on a good day, when the light filters down through the kelp, the place just glows. Our favourite thing about Arachne has to be the sheer variety of critters tucked into every crevice. We’ve spent entire dives just poking around, spotting slender blade shrimp camouflaged against the rocks, and those oddly charming sweet potato sea cucumbers. Keep an eye out for the four-spined squat lobsters; they’re little characters. You’ll also find plenty of dungeness crab scuttling about. It’s a dive that rewards slow, deliberate exploration. This site is perfect for divers who appreciate the subtle beauty of temperate waters and don't need huge pelagics to feel fulfilled. It’s a fantastic spot for macro photographers, or anyone who enjoys patiently observing behaviour rather than just ticking off big species.
- Location
- Pacific Northwest, United States, North America
- Coordinates
- 48.684723, -123.293680
- Type
- reef
- Maximum Depth
- 5-20m
Marine Protected Area: Kellett Bluff Voluntary No-take
Best Time to Dive in Pacific Northwest
The warmest water temperatures in Pacific Northwest occur in August, averaging 16.5°C (up to 15.6°C). The coolest conditions are in February at 6.9°C.
Monthly Water Temperatures
- January: 7.1°C (air: 6.3°C)
- February: 6.9°C (air: 4.5°C)
- March: 7.7°C (air: 6.6°C)
- April: 9.5°C (air: 8.7°C)
- May: 12.0°C (air: 11.7°C)
- June: 14.0°C (air: 13.7°C)
- July: 15.7°C (air: 14.9°C)
- August: 16.5°C (air: 15.7°C)
- September: 14.3°C (air: 14.0°C)
- October: 11.4°C (air: 10.5°C)
- November: 8.8°C (air: 7.4°C)
- December: 7.7°C (air: 5.5°C)
Nearby Dive Sites in Pacific Northwest
- 100 Foot Rock
- Alki Beach Park
- Alki beach Seattle ferry north
- Am/Pm Beach - 13m (shore)
- Ansell Point Dive Site - 5-20m (shore)
- Arachne Reef (reef)
- Arbutus Island - 10-30m (shore)
- Arbutus Point - 23m
- Atkins Reef (reef)
- Atrevida Reef (reef)
- Barnard Castle - 15-35m (pinnacle)
- Bell Island
- Blake Island Reef (reef)
- Blind Reef (reef)
- Boiling Reef (reef)
Nearest Dive Centres to Arachne Reef
Marine Life in Pacific Northwest
Home to 38 recorded species including 18 reef fish, 7 crabs & lobsters, 3 whales & dolphins, 2 sharks & rays, 2 clams & mussels, 2 sea urchins.
Notable Species
- Pacific herring (Clupea pallasii) - Reef Fish
- coho salmon (Oncorhynchus kisutch) - Reef Fish
- Spiny Dogfish (Squalus suckleyi) - Sharks & Rays
- Chinook (Oncorhynchus tshawytscha) - Reef Fish
- Dungeness Crab (Metacarcinus magister) - Crabs & Lobsters
- Common shore crab (Carcinus maenas) - Crabs & Lobsters
- red salmon (Oncorhynchus nerka) - Reef Fish
- California Spot Prawn (Pandalus platyceros) - Crabs & Lobsters
- Slender Crab (Metacarcinus gracilis) - Crabs & Lobsters
- Rainbow Trout (Oncorhynchus mykiss) - Reef Fish
- Whiting (Merluccius productus) - Reef Fish
- Pacific krill (Euphausia pacifica) - Crabs & Lobsters
- Common Seal (Phoca vitulina) - Whales & Dolphins
- Eulachon (Thaleichthys pacificus) - Reef Fish
- Red Rock Crab (Cancer productus) - Crabs & Lobsters
- Spotted Ratfish (Hydrolagus colliei)
- Calico salmon (Oncorhynchus keta) - Reef Fish
- Slender Sole (Lyopsetta exilis) - Reef Fish
- Pacific Geoduck (Panopea generosa) - Clams & Mussels
- Olympia oyster (Ostrea lurida) - Clams & Mussels
Recommended Packing List for Arachne Reef
Based on average water temperature of 11.0°C, currents 7 cm/s.
- Wetsuit (5-7mm) - recommended for 11°C water
- Hood & Gloves (3-5mm) - helps retain warmth
- Mask - essential for every dive
- Fins
- BCD - buoyancy compensator
- Regulator - your most safety-critical piece of gear
- Dive Computer - tracks depth, time, and NDL
- Surface Marker Buoy (SMB) - essential for boat pickups
- Dive Torch - useful for crevices and colour at depth
- Underwater Camera - capture your diving memories