Seattle's Sound Transit has two Link openings planned this year:
East Link (Two Line) will open a starter line April 27. This is only from South Bellevue to Redmond Tech Station. The Seattle connection needs some rework and will open next year. An extension to Downtown Redmond was always going to be next year. The Seattle extension will also use the existing One Line rails northward through town, improving frequency.
Lynnwood (the latest One Line extension to the north, with another planned) will open August 30.
Federal Way (the latest One Line south extension, with another planned) will open in 2026.
We're still trying to figure out the alignment and stations for the Ballard and West Seattle lines, with further study before the final EIS because leadership keeps thinking of new ideas and cost estimates have risen.
https://www.soundtransit.org/system-expansion