Ft. Casey Underwater State Park, better known as Keystone, is just one of the many easily accessible training sites in northwest Washington State. The dive site is popular with divers from both Seattle, Wash., and Vancouver, B.C.

Ft. Casey Underwater State Park offers two distinctly unique dive sites, Keystone Jetty and the abandoned dock pilings. Visibility at both sites varies between 10-50 feet/3-15 meters. Water temperature may drop as low as 45 degrees F/7 degress C in winter; 52 degrees F/11 degrees C is the typical water temperature in summer. A dry suit is the recommended exposure protection, although a full 6.5mm-thick wet suit with booties, hood and gloves may be sufficient.

Keystone jetty is about 250 feet/76 meters long with a maximum depth of about 65 feet/20 meters, depending on the height of the tide. There are a number of two-foot-high, white plumose anemones on the boulders around the jetty. The rocks are also dotted with large starfish, barnacles and tube worms.

Giant Pacific octopus, which can attain an arm span of over 10 feet/3 meters, can be seen resting in their dens among the boulders by the jetty. A pile of broken crab shells is the telltale evidence that an octopus may be nearby. Occasionally, giant wolf eels are also seen in the area. It’s common to observe schools of surfperch swimming along the boulders and rockfish hovering in the bull kelp.

The abandoned dock attains a depth of 30-40 feet/8-12 meters at the outer edge. This makes a good place for divers to tune up their neutral buoyancy skills. Buddies can also challenge their underwater navigation skills by drift diving over the smooth, sandy bottom between the dock and jetty.

Marine life on the old dock pilings includes yellow sponges, red tunicates, decorator crabs and barnacles, just to name a few. On the loose rock bottom, you’ll find fish like the buffalo sculpin, kelp greenling, lingcod and the great cabezon. Beyond the pilings, the sea floor gently drops deeper and is dotted with orange and red filter feeders called burrowing sea cucumbers.

Predive planning is particularly important when diving Keystone. Brisk tidal currents, southeast wind, kelp and the ferry are notable hazards at the site.

As is typical of most Pacific Northwest dive sites, current is a dominant factor in planning a dive. You must plan to dive during the slack period when the tide turns to a flood or an ebb. To find the time of a predicted slack, check with a tide and current table book. The tables and other important weather information are available by checking with dive centers in the area.

The waves created by the southeast winds can sometimes make the beach entry very difficult, like that of the open coast. Wandering around the tip of the jetty takes you into the stronger currents, which can carry you dangerously close to the path of a Washington State Ferry. Be sure to keep track of your position both underwater and topside to avoid the stronger currents and the shipping traffic.

Ft. Casey State Park is open year-round. Facilities include a changing room with coin-operated hot showers and lavatory. An outside cold shower is also provided to rinse the saltwater and sand off your dive gear. Picnic facilities, camping sites and a boat launching ramp are also available. Air fills are available in the dive center in Oak Harbor, about 30 minutes away.

In case of an emergency, the nearest public telephone is located at the Keystone/Port Townsend ferry terminal. Nearby Coupeville, Wash., has a hospital. A hyperbaric chamber is located in Seattle at the Virginia Mason Hyperbaric Unit. In the event of an emergency, dial 911.

To get to Fort Casey Underwater State Park from Seattle, take Interstate 5 north for about 50 miles/80 km. Turn off via the Clinton/Mukilteo Exit No. 182. Proceed north on Hwy. 525 to Mukilteo, where you’ll board a state ferry for the 20-minute ride to Clinton on south Whidbey Island. Continue north on Hwy. 525 towards the seaside town of Coupeville. Turn left onto Engle Road and follow it to the Keystone/Port Townsend ferry terminal. The underwater park is right beside the ferry terminal.

From Vancouver, British Columbia, the park is about 120 miles/192 km south. Drive south on Interstate 5 to the Anacortes turnoff at Exit No. 230. Continue west on Hwy. 20 to where signs point onto Whidbey Island across the Deception Pass bridge. Past the town of Oak Harbor is Coupeville. Turn right onto Engle Road to get to the park.