For a leisurely scenic drive, head along the water on Harbor Avenue SW to Duwamish Head, then west on Alki Avenue SW to Alki Beach Park, a long, narrow, sandy stretch—as close to a real beach (outside Golden Gardens) as you'll find on this part of Puget Sound.
In warm weather a whole beach culture emerges here—cruising cars, illegally parked vehicles, bonfires, suntan goop, the works—even though the water rarely gets above 55°F.
Keep going on Alki Avenue to the Alki Point Lighthouse (206/286-5423). Tours of the station are available weekdays by reservation.