Central Link construction was delayed because of funding issues and routing disputes, but began in November 2003 and was completed on July 18, 2009, for $2.4 billion. Tacoma Link began construction first in 2000 and opened on August 22, 2003, at a cost of $80 million. Sound Transit was created in 1993 and placed a ballot measure to fund and build the system, which was passed on a second attempt in 1996. The Link light rail system was originally conceived in the 1980s following several earlier proposals for a heavy rail system that were rejected by voters. In 2022, the system had a ridership of 23,905,500, or about 75,000 per weekday as of the fourth quarter of 2022, primarily on the 1 Line, and runs trains at frequencies of 6 to 24 minutes.

It is managed by Sound Transit in partnership with local transit providers, and consists of two non-connected lines: the 1 Line (formerly Central Link) in King County, which travels for 25 miles (40 km) between Seattle and Seattle–Tacoma International Airport and the T Line (formerly Tacoma Link) in Pierce County, which runs for under 2 miles (3.2 km) between Downtown Tacoma and Tacoma Dome Station. Link light rail is a light rail rapid transit system serving the Seattle metropolitan area in the U.S.

Othello light rail station