Link is a light rail system operated by Sound Transit that serves the Seattle metropolitan area in the U.S. state of Washington. The network consists of 31 stations on two unconnected lines: nineteen on the 1 Line and twelve on the T Line in Tacoma. Link stations are located within four cities in King and Pierce counties: fourteen in Seattle, twelve in Tacoma, two in SeaTac and one in Tukwila. The two lines had a combined average weekday ridership of 82,783 and total ridership of 26 million in 2019, placing it seventh among the busiest light rail systems in the United States. The busiest station by daily ridership is Westlake station in Seattle, while the least busy is Convention Center/South 15th Street station in Tacoma.
The first Link segment began service on August 23, 2003, with the opening of five stations on the Tacoma Link (now the T Line). The initial, segment of Central Link (now the 1 Line) with 12 stations was opened from Seattle to Tukwila on July 18, 2009, and was later extended to the Seattle–Tacoma International Airport on December 19, 2009. The first infill station of the Link system was Commerce Street/South 11th Street station on the T Line, which opened on September 15, 2011. The 1 Line was extended north to the University of Washington on March 19, 2016, and south to Angle Lake station on September 24, 2016. A northern extension to Northgate station with three stations opened on October 2, 2021. The T Line was extended in September 2023 with six new stations and one relocated stop.
, Sound Transit is building four extensions of the Link network that will open between 2024 and 2026 with 20 new stations. Among these are the 2 Line with ten stations from Seattle to Bellevue and Redmond on the Eastside, scheduled to open in two phases split between 2024 and 2025; and extensions of the 1 Line north to Lynnwood in 2024 and south to Federal Way in 2026. These extensions are planned to add an additional to the light rail network, carrying an estimated 280,000 daily riders by 2030.
Further expansions approved by Sound Transit 3 in 2016 are planned to expand the light rail network by and 39 stations to a total of of track and 70 to 75 stations by 2044, carrying 500,000 daily passengers. The light rail network will include lines to Ballard and West Seattle in Seattle in 2039 and 2032, respectively; Kirkland and Issaquah on the Eastside in 2044; and extensions to Everett and Tacoma in 2041 and 2032, respectively. Three infill stations in Seattle and Tukwila will also be built as part of the Sound Transit 3 program.
All 1 Line light rail stations are built with , platforms, arranged in the center or sides of the two tracks, with capacity to handle a four-car train with vehicles; T Line stations are built with , platforms that can accommodate a one-car train measuring in length. The majority of stations are built at-grade on the surface, with the platform elevated slightly above street level; there are also elevated stations and underground stations that include mezzanines (with the exception of Mount Baker station) with access the platform from the surface as well as ticket vending machines and bicycle facilities. Only four current stations (Angle Lake, Northgate, Tacoma Dome Station, and Tukwila International Boulevard) have public park and rides; planned stations on the suburban extensions of Link will incorporate new or existing park and rides.
All stations include works of public art as part of the "STart" program, which requires one percent of station construction funds go to art installations. The stations are named in accordance to facility naming guidelines that include using surrounding neighborhoods and street names, avoiding words used by existing facility names, and being limited to 30 characters in compliance with the Americans with Disabilities Act. Stations are also required by state law to be identified by simple pictograms, known as "Stellar Connections", that are used in station signage, maps and other printed materials as a wayfinding aid; the icons are composed of points that correspond with local landmarks near Link stations, while also forming a picture that represents the station's identity.