Crews working on the Federal Way Link Extension will be closing SR 99 between South 204th Street and South 208th Street in SeaTac to return the route to its original configuration, Sound Transit announced.

Sound Transit had built a temporary bypass in order to construct the elevated light rail guideway.

All lanes of SR 99 will be closed beginning this Friday, July 29, 2022 at 10 p.m. They are expected to reopen at 5 a.m. on Monday, Aug. 1. Drivers will be detoured around the closure on 24th Ave South.

This work is weather dependent.

Work will take place around the clock for the full weekend.

Crews will try to reduce noise when possible.

Completion of construction will also mark the opening of the SR 99 bridge, a major milestone for the Washington State Department of Transportation’s (WSDOT) SR 509 Completion Project.

In an effort to reduce construction-related costs, timelines, and impacts on nearby communities, Sound Transit is administering Stage 1a of WSDOT’s SR 509 Completion Project as an integrated part of the Federal Way Link Extension project. The future SR 509 Expressway will travel under the new SR 99 bridge, connecting I-5 to SR 509 where it currently ends at the southwest corner of Sea-Tac Airport.

For more information on the Federal Way Link Extension and to sign up for project updates, visit