Some of the best marine ecosystems to explore from a public access state park are located on Whidbey Island, the largest (or at least the longest) island* that is exposed to direct tidal flows that surge from the Pacific Ocean up into the Inside Passage.
*(thanks to the mighty Deception Pass)
For these (and more) reasons, the Keystone Jetty rates as one of the top convenient dive sites in the Puget Sound!
For the ‘TL;DR’s among us, here is a video highlighting some of why this semi-artificial reef** is so popular:
**(Washington State Ferries was kind enough to install a large jetty of giant boulders at Keystone to shelter the terminal from strong weather and currents, which now is tidal sieve and home for any and all marine species that swim, drift, crawl or slither.)
Keystone is a favorite for those located along the upper I-5 corridor, as it is one of the most reasonable and convenient kelpy rock reefs you can get to as a day trip from the cities.
Understanding how to time the dives here is crucial for safety and enjoyment, as 3+ knot currents drain this area into the very deep (and often rough) Admiralty Inlet.
For dive planning, please check pnwdiving.com, or the NOAA resources if you want to really dive into the data.
Click here for slack tide suggestions for Keystone Jetty:
Currents can be challenging and deceiving, so it is recommended that you dive with someone who has experience with the site, a local dive shop, or guide.
The jetty is a marine park and closed to fishing, spearing, taking, trapping or collecting–except on the part of the rocks that faces the ferry. Families fish on the ferry side, and divers regularly explore and monitor the protected side. Nearby Driftwood Park is better for salmon fishing, but the boat ramp at Keystone is very busy during the season!
As for the history of Keystone, this was an essential part of native lands for resident and seafaring local first nations, was integrated into one of the first rural homestead communities the state (now the Ebey Reserve), and hosts a formidable WWII artillery fortress (Fort Casey) that now entertains thousands as a scenic historical park (and camp).