Posey Island Marine State Park
05 reviewsPosey Island Marine State Park
Quick Facts
Price
Varies
Booking
Reservable
Sites
2 campsites
Season
Year-round
Cell
Unknown
Pets
Not Allowed
Quick Facts
Price
Varies
Booking
Reservable
Sites
2 campsites
Season
Year-round
Cell
Unknown
Pets
Not Allowed
Posey Island Marine State Park
No fees available
Campsite Fees
Fee information not specified in the provided sources. The park consists of two primitive group campsites; no potable water and limited facilities...
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Standard Site Fee$0.00
Hookup Site Fee$0.00
Premium Site Fee$0.00
Hike and Bike Site Fee$0.00
Group Site Fee$0.00
Food Storage Locker Fee$0.00
Total Campsite Fees$0.00
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Going To Camp
ProviderWhat Campers Say
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Limited Reviews
Based on 5 reviews
14 Google reviews
Most mentioned
viewscleanshadebeach
Some mention
crowded
"Reviews emphasize a beautiful, quiet, classic San Juan Islands kayak campsite with two primitive sites, a composting outhouse, good beach access, and strong paddler appeal. Visitors repeatedly note lack of potable water and limited capacity; many reviewers rate the site very highly for scenery and beachcombing."
Best Time to Camp at Posey Island Marine State Park
Mother Nature keeps things interesting here—the island's exposed position means wind is a frequent companion, adding drama to your adventure. Visit during shoulder seasons like March for an almost guaranteed private island experience, though you'll want to pack warm layers for those crisp marine breezes. Smart paddlers always check marine weather and tide forecasts before setting out, ensuring your island getaway is memorable for all the right reasons.
Spring (Mar-May)
Wildflowers bloom, mild temperatures, fewer crowds. Great for hiking and photography.
Best
Summer (Jun-Aug)
Peak season with warm weather, perfect for water activities. Book early.
Fall (Sep-Nov)
Beautiful fall colors, cooler temps, quieter campgrounds. Ideal for peaceful trips.
Winter (Dec-Feb)
Off-season, limited services. Check for closures before visiting.
Planning Tips
About Posey Island Marine State Park
Escape to your own private island paradise at Posey Island Marine State Park, a jewel-box one-acre retreat in the San Juan Islands accessible only by boat. This intimate marine sanctuary offers just two primitive group campsites where kayakers and paddlers can claim their own slice of wilderness, complete with sweeping views across the Haro Strait and the kind of solitude that makes you feel like a true castaway.
Small, primitive marine campsite setting with two reserved group sites on a tiny one‑acre island; boat‑in only.
Weather and SeasonsMother Nature keeps things interesting here—the island's exposed position means wind is a frequent companion, adding drama to your adventure. Visit during shoulder seasons like March for an almost guaranteed private island experience, though you'll want to pack warm layers for those crisp marine breezes. Smart paddlers always check marine weather and tide forecasts before setting out, ensuring your island getaway is memorable for all the right reasons.
Natural Features and SceneryPicture yourself exploring rocky saltwater shores dotted with cozy pocket beaches, where driftwood logs create natural seats for watching the world go by. The island's heart is a charming meadow that bursts with wildflowers in season, framed by stately fir trees and surrounded by endless marine vistas. This undeveloped gem is a front-row seat to nature's theater—watch for seals popping up in the kelp beds, seabirds diving for their dinner, and the occasional orca fin slicing through distant waters. Every corner of this tiny island invites quiet exploration and discovery.
Geological RegionSan Juan Islands (Haro Strait), Salish Sea
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Campsite details
Total Campsites2 campsites
Best Campsites
Curated by campers, for campers
Reveal picks
Reserving a campsite
Tents
Tents are allowed
RV vehicles
RV vehicles are not allowed
Primitive
Primitive are allowed
Reservable
Reservations are allowed
Reservation PlatformsGoingToCamp (https://washington.goingtocamp.com)
Accomodation available
GroupGroup campsites are offered for larger parties such as families, schools, or organizations. These sites provide space and facilities to accommodate multiple people camping together.
Amenities available
Fire rings
Picnic tables
Activities you can enjoy
Marine/island activities focused on paddling and beach exploration. Common uses include kayaking, paddleboarding, swimming, fishing, crabbing, bird and marine wildlife viewing, and short walks/beachcombing.
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Campground rules
- Pets are not allowed
- A fire ring is present at one campsite per trip reports; follow Washington State Parks fire restrictions and bans (specific policy details not provided).
Hazards
General hazardsWind exposure and weather; strong currents and tide shifts in nearby channels (notably around Spieden Island) can create challenging crossings. No potable water or garbage service — pack in/pack out required.
Weather at Posey Island Marine State Park
49
°F
Dec 14
Sunday
Overcast
Precipitation: 0%
Humidity: 84%
Wind: 7.9 mph
Overcast
Weather History
Weather data powered by Open-Meteo
Detailed 7-Day Forecast
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Reveal forecast
Emergency Services
Roche Harbor resort/marina and facilities on San Juan Island (launch point and services).
Good to know
Common complaintsVery limited capacity (only two sites) can feel crowded in summer; no potable water or services; exposed/windy conditions at times; access limited to boat‑in visitors.
Campground Map
Posey Island Marine State Park
Driving directionsBoat-in only. Access by human- or wind-powered watercraft from Roche Harbor and other San Juan Island launch points; no road or dock access on Posey Island.
No road access — island is reachable only by boat. Overnight camping restricted to human- or wind-powered watercraft; motorboats limited to day use.Nearby supplies
Roche Harbor marina/resort and San Juan Island facilities (launch points and supply locations).
Reviews from booking and map sources
0.0
5 reviews
Posey Island Marine State Park has limited reviews, placing it in the bottom % of campgrounds based on reviews
Reviews emphasize a beautiful, quiet, classic San Juan Islands kayak campsite with two primitive sites, a composting outhouse, good beach access, and strong paddler appeal. Visitors repeatedly note lack of potable water and limited capacity; many reviewers rate the site very highly for scenery and beachcombing.
Review Summaries
Based on 5 reviews
What Campers Love
Scenic, remote one‑acre island ideal for kayakers and paddlers; clean composting outhouse; gravel beaches, good landing sites, shade from trees, excellent sunset views, and dark night skies for...
Based on 5 reviewsShow more
Common Concerns
• **Very limited capacity and potential crowding**: With only two group sites on a one‑acre island, several sources imply that **summer can feel crowded**, especially when commercial kayak tours stop...
Based on 5 reviewsShow more
Pro Tips & Recommendations
Reserve in advance (only two sites). Pack all drinking water and pack out trash. Arrive by human‑ or wind‑powered craft for overnight stays; motorboats are day‑use only. Choose the more sheltered...
Based on 5 reviewsShow more
Camper Quotes
"Absolutely beautiful. Kids had tons of fun looking at all the little rock crabs on the beach."; "Wonderful park to camp at. There are only 2 campsites and there is one composting toilet in an...
Based on 5 reviewsShow more
Camper Reviews by Outdoorithm campers
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Last updated December 14, 2025
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