Sound Transit

About

The Central Puget Sound Regional Transit Authority, branded as Sound Transit (ST), is a public transit agency serving the Seattle metropolitan area in the U.S. state of Washington. It manages the Link light rail system in Seattle and Tacoma, regional Sounder commuter rail, and Sound Transit Express bus service. The agency also coordinates with the regional ORCA fare card system used by transit operators across the metropolitan area. In 2025, Sound Transit services carried approximately 51 million total passengers and averaged over 153,000 riders on weekdays.

The agency was created in 1993 by King, Pierce and Snohomish counties to build a regional rapid transit system. After an unsuccessful proposal in 1995, the "Sound Move" plan for regional light rail, commuter rail, and express bus service was approved by voters in November 1996. Sound Transit began operating its express bus service in September 1999, taking over existing routes from local transit agencies. The region's first commuter rail line, between Tacoma and Seattle, started in December 2000; the agency's first light rail line, Tacoma Link (now the T Line), began service in August 2003. Light rail service in Seattle on Central Link (now the 1 Line) began in 2009, and is the largest part of the Sound Transit system in terms of ridership. Union Station in Seattle has served as the agency's headquarters since its renovation in 1999.