Turn Island State Park
San Juan Islands · United States
Turn Island Marine State Park sits just east of Friday Harbor on San Juan Island, surrounded by a protected marine waters area. Rocky reefs at 12 to 22 m are carpeted with giant Pacific octopus dens, white and orange plumose anemones, and thick beds of purple sea urchins. Bull kelp forests grow to 15 m at the south end of the island and shelter lingcod, cabezon, and schools of black rockfish. The tidal channel between Turn Island and San Juan Island produces gentle drift conditions on the slack, making it ideal for intermediate divers who want their first taste of Pacific Northwest cold water.
Conditions
Depth
5 to 22 m
Open water and up
Current
Usually gentle
Can pick up on the edge
Visibility
5 to 9 m
Clearest in the calm season
Water
7 to 13°C
drysuit required
Month by month
| Month | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Water (°C) | 7 | 7 | 7 | 8 | 9 | 10 | 11 | 11 | 10 | 9 | 8 | 7 |
| Vis (m) | 10 | 10 | 8 | 8 | 6 | 6 | 5 | 5 | 6 | 10 | 10 | 10 |
| Current | Moderate | Moderate | Moderate | Moderate | Moderate | Gentle | Gentle | Gentle | Moderate | Moderate | Moderate | Moderate |
Your chances of seeing each animal
Kelp Crab
Last confirmed Jun 30, 2026 · 174 records
Almost always
Nearly every dive
Bull Kelp
Last confirmed Jul 6, 2026 · 254 records
Almost always
Nearly every dive
Giant Pacific Octopus
Last confirmed Apr 7, 2026 · 38 records
Very likely
Most dives
Purple Sea Urchin
Last confirmed Apr 19, 2026 · 21 records
Very likely
Most dives
Plumose Anemone
Last confirmed Feb 3, 2026 · 13 records
Very likely
Most dives
Lingcod
Last confirmed May 15, 2026 · 10 records
Very likely
Most dives
Cabezon
Last confirmed Jun 2, 2026 · 5 records
Very likely
Most dives
Giant Green Anemone
Last confirmed Jun 25, 2026 · 5 records
Very likely
Most dives
Gear