Washington State runs the largest ferry fleet in the world, connecting mainland cities to islands through the sound, to the Olympic Peninsula, the San Juan Islands and Vancouver Island.
You can walk on any of them and take a nice round trip boat ride.

British Columbia operates four ferry lines between the mainland (“Sunshine Coast”) and Vancouver Island.

A ferry crossing of Jarvis Inlet from Earl's Cove to Saltery Bay (the crossing is in effect part of British Columbia highway 101) provided Joan and me with an indelible memory. We crossed just before sunset under glowering clouds. The ten mile crossing takes about 50 minutes. A curtain of black mountains surrounded us. There seemed to be no lights anywhere except those on the ferry itself. The darkness subdued us and our few fellow passengers. Joan and I huddled at the rail feeling something close to fear.