SR 99 closures at Seattle’s downtown tunnel this week
Dec 1, 2025, 2:10 PM
Freshly painted lane stripes on the northbound (lower) deck of the SR 99 tunnel (Photo courtesy of WSDOT)
(Photo courtesy of WSDOT)
The Washington State Department of Transportation (WSDOT) has scheduled a number of lane and ramp closures this week at or near Seattle’s downtown tunnel on SR 99. If this is your regular route, you will need to plan for detours and closures starting late in the evening and wrapping up before the early morning rush.
Closures change nightly
Monday night: From 9 p.m. Monday, Dec. 1, to 5 a.m. Tuesday, Dec. 2, the right lane of the northbound SR 99 tunnel will close. The Royal Brougham Way on-ramp to northbound SR 99 and the northbound SR 99 off-ramp to Republican Street will close at the same time.
Tuesday night: From 9 p.m. Tuesday, Dec. 2, to 5 a.m. Wednesday, Dec. 3, the two left lanes of southbound SR 99 will close north of the tunnel. The southbound SR 99 off-ramp to Harrison Street will close at the same time.
Wednesday night: From 9 p.m. Wednesday, Dec. 3, to 5 a.m. Thursday, Dec. 4, the Sixth Avenue N. on-ramp to southbound SR 99 will close.
Friday night into Saturday: WSDOT will close both directions of the SR 99 downtown tunnel for regular maintenance. The tunnel will close between 10 p.m., Friday, and 6 a.m., Saturday.
Drivers can avoid these closures on SR 99 by rerouting travel to I-5.
WSDOT maintenance crews will use this closure to remove existing vegetation for later replanting.
Nate Connors is a traffic reporter for KIRO Newsradio. Follow him on X. Read more of his stories here. Submit news tips here.
