The Federal Way Link Extension is a planned Link light rail extension of the 1 Line that will travel 7.8 miles (12.6 km) south from Sea-Tac Airport to Federal Way, along the west side of Interstate 5. It was approved in 2008, but scaled back in 2010 to terminate at Kent Des Moines station. The Star Lake and Federal Way Downtown stations were re-instated in 2016, with the passing of Sound Transit 3. The project began construction in 2020 and is expected to open in 2026.

Federal Way is a city in King County, Washington, United States and part of the Seattle metropolitan area. One of the most recently incorporated cities in the county, its population was 101,030 at the 2020 census. Federal Way is the 10th most populous city in Washington and the 5th most populous in King County.