West Seattle and Ballard Link Extensions

Alignment

Voters approved both extensions in Sound Transit 3 (ST3) in 2016, and Sound Transit planned them together as the West Seattle and Ballard Link Extensions. In October 2023 Ballard Link was split off as a standalone project because design changes in downtown Seattle were delaying its environmental review. The two now have separate environmental processes, budgets and schedules. West Seattle Link will open first, as the first phase of the future 3 Line. Until Ballard Link opens, a rebuilt SODO station will be the transfer point for all West Seattle riders.

The West Seattle Link Extension runs 3.9 miles from a rebuilt SODO station to Alaska Junction. It crosses the Duwamish River on a new light-rail-only bridge and runs on elevated guideway through Delridge. It then enters a tunnel near the Nucor steel mill to reach a shallow underground station at Alaska Junction. The Delridge station will be elevated, with side platforms. The Avalon station approved by voters was dropped in 2026 to save money, which leaves two new stations plus the rebuilt SODO station.

The Ballard Link Extension would add 7.7 miles and up to nine stations between SODO and Ballard, including a second downtown light rail tunnel. Under the preferred alternative chosen in 2023, the tunnel would serve the Chinatown–International District, downtown (where station sites are still under study), an expanded Westlake, Denny, South Lake Union and Seattle Center. The line would then emerge near Republican Street and 5th Avenue West and continue elevated beside the BNSF tracks to Smith Cove and Interbay. A tunnel under Salmon Bay would lead to an underground Ballard station at NW Market Street and 15th Avenue NW, and a fixed-bridge crossing is also under study. The 2026 plan funds construction only as far as Seattle Center. Smith Cove, Interbay and Ballard still need $7–9 billion more.

Updates

2026-10 — Ballard Draft EIS scheduled; cost-cutting push continues

Sound Transit scheduled the Ballard Link Draft EIS for December 11, 2026, with a 60-day comment period, and said it would include a station-consolidation option. The agency said it had already built up to $4 billion in savings into the design and opened procurement for an engineering partner to find more. It is also weighing partial automation through communications-based train control. An elevated downtown alignment and full automation were considered and set aside.

2026-08 — West Seattle opening moves to 2035

Sound Transit moved West Seattle Link’s opening from 2032 to 2035. It cited the cost-savings redesign, which identified more than $2 billion in savings, and the time needed to build the new Duwamish crossing. A new SODO design keeps Seattle City Light’s 230-kilovolt transmission lines within the light rail corridor instead of moving them onto 6th Avenue S. Major contracts for the bridge, tunnel, guideways and stations are expected to be awarded in 2027.

2026-07 — Ballard dates set at 2042, or as late as 2060

Sound Transit said the funded segment to Seattle Center would open in 2042, later than the previous 2039 target. The full line to Market Street could open in 2042 only if the agency finds about $1 billion for property acquisition by 2030, completes final design by 2032, and secures construction funding by 2033. Without new savings or financing, service to Smith Cove, Interbay and Market Street could slip to around 2060.

2026-06 — West Seattle enters final design

The Board approved a $341 million final-design contract with Jacobs Engineering and a $48.7 million project-management contract for both extensions. That raised West Seattle’s approved budget by $406.8 million. Station designs were slimmed down at SODO, Delridge and Alaska Junction, and the Avalon station was removed.

2026-05 — Board adopts a restructured ST3 plan

Facing a projected long-term shortfall of about $35 billion, which the agency is tackling through its agencywide “Enterprise Initiative”, the Board voted 16–2 on May 28, 2026, to adopt a restructured ST3 System Plan. The plan funds West Seattle Link, without Avalon station, for immediate progress. It funds Ballard Link construction only to Seattle Center and commits to completing design for the full line. Another amendment required Sound Transit to publish a Ballard opening date range by August 2026.

2025-08 — Ballard estimate climbs to $20.1–22.6 billion

An updated agency financial plan raised Ballard Link’s estimate to $20.1–22.6 billion, up from $11.2 billion when it became a standalone project in 2023. A study released in December 2025 looked at avoiding the second downtown tunnel. It considered running three lines through the existing transit tunnel, or a “stub end” line from Ballard to Westlake, and estimated possible savings of up to $4.5 billion.

2025-04 — Federal Record of Decision for West Seattle

The FTA approved the Record of Decision for West Seattle Link, completing its federal environmental review. The Board had chosen the route and station locations in October 2024, after estimates showed costs had risen about 75% from the original $4 billion budget. At the time of the decision, the project was estimated at $6.7–7.1 billion.

2023-10 — Ballard Link split from West Seattle

Changes to the downtown and Chinatown–International District stations, including split “North of CID” and “South of CID” stations added to the preferred alternative in March 2023, added about two years to Ballard’s planning. Sound Transit separated the projects so West Seattle’s environmental review could proceed on its own. Ballard then needed its own Draft EIS, and a new scoping process began in October 2024.