Edmonds Underwater Park
Edmonds Underwater Park is probably the most popular dive location in the Pacific Northwest. It is shallow ( 35'), with very easy access. The site has restrooms and changing rooms as well as a fresh water shower for rinsing off divers and their gear.
There are lots of "enhancements" in the park for divers to look at, thanks to the tireless work of Bruce Higgins, the parks curator. My favorite is the "Triumph", a wooden tug that was sunk in the park. It is still largely in one piece, although crumbling fast.
The tug has gone from bare wood to living reef in just a few short years. It is covered with kelp and schools of fish that shimmer in the current.
There are also lots of HUGE fish in the park. The ling cod and Cabezon are really big. They are very used to lots and lots of divers, so allow you to get quite close. This is also a good site to spot one of my favorite Pacific Northwest fish, the Ratfish! They are so ugly, they are cute.
For more information (including directions), see the excellent reviews of Edmonds Underwater Park at Shorediving.com.