Whittier & Prince William Sound

The diving is run from Anchorage, about 45 minutes' drive from the tunnel entrance: Dive Alaska guides in the Sound from its Anchorage shop, Last Frontier Diving takes open-water students to Whittier or Seward for their four ocean dives, and divers collect and return their own gear at the shop. The road reaches town through the Anton Anderson Memorial Tunnel, which opens to one direction every half hour. Smitty's Cove is dived from the shore in town, and a Whittier-based charter boat carries divers out into the Sound.

Smitty's Cove is a protected marine park with a history reaching back to the Second World War, and its bottom holds wartime wreckage, industrial slag, NOAA reef installations and sunken cranes and planes. Kittiwake Rookery, directly across the bay where three large waterfalls pour into the water beneath the colony, begins as a gradual slope, turns into a steep wall and a canyon, and from 30 m (100 ft) becomes a sheer face; past 40 m (130 ft) the topography gives way to giant sea sponges. Nudibranchs, rockfish and brittle stars live on the wall, and the Dutch Group islands hold Great Pacific octopus, wolf eels and giant crabs.

The Sound suits self-reliant drysuit divers who handle their own gear and plan a dive day like a backcountry trip, in water that runs from 2 °C to 13 °C (36–55 °F) over the year. Currents vary and can run strong on the large tides, and the Rookery wall continues below 40 m. Smitty's Cove is Anchorage's go-to winter training site and is hard to dive from late May to early September.