The Seattle area currently has a good mass transit system.

Seattle is located in King County. King County Metro is a county-owned public transit system consisting almost entirely of buses. The only exception is the new South Lake Union Streetcar. There was also a Waterfront Streetcar, but that line has temporarily been replaced by a bus pending contruction of a new maintenance barn.

Metro uses a very good mix of various types of buses providing both local and express service throughout King County. A bus tunnel under Downtown Seattle is used by many of the buses, providing faster trips through the downtown core and reducing the number of buses on surface streets. When the light rail line begins operations in 2009 the tunnel will be used by both light rail trains and buses.

The next county south of King County, Pierce County, also has a county-owned bus system called Pierce Transit. It provides service within Pierce County, including its largest city, Tacoma.

The county immediately north of King County, Snohomish County, has a public bus system called Community Transit.

The largest city in Snohomish County, Everett, has its own bus system, Everett Transit.

In addition to the county and city systems, there is a regional transit authority known as Sound Transit. Sound Transit operates a number of express bus routes and limited commuter rail service between Seattle, Tacoma, and Everett. They also operate a short light rail line in Tacoma and construction is underway on a longer light rail line from Downtown Seattle to Sea-Tac Airport, a few miles south of Seattle. Sound Transit is also planning to extend the light rail line north from Downtown Seattle to the University of Washington, and then to Northgate. They are also proposing extending light rail across Lake Washington from Seattle to the Eastside cities of Bellevue and Redmond.