The Port of Seattle Commission authorized initial funding today for the next significant modernization project at Seattle-Tacoma International Airport (SEA) — the S Concourse Evolution (SCE) — with major construction scheduled to start in 2027. As part of the $5.5 billion Upgrade SEA capital improvement program, the estimated $2.5 billion S Concourse renovation will transform a 1973 facility into a world-class concourse that primarily serves international travelers. The project matches recent SEA modernization project standards, ensuring increasing traveler demands are met with more space, amenities, and sustainability, including reduced energy use and greenhouse gas emissions.
“Today’s authorization to move forward with the S Concourse Evolution builds on the generational investments we are making at SEA to improve the passenger experience,” said Port of Seattle Commission President Ryan Calkins. “The project will add critical seismic, structural, and building systems upgrades to improve long-term passenger circulation as well as operational efficiency.”
The project does not increase gate count on that concourse, as there is no room to expand between the main terminal and the airfield. Instead, it repurposes, in part, the customs area vacated when the International Arrivals Facility (IAF) opened in 2022. The modernization will add 150,000 square feet, including a new Upper Concourse Level, improved dual-level boarding operations for select gates, and expanded dining, retail, lounge, and passenger amenities.
“The existing building is over half a century old, making it challenging for us to meet our goals of providing the best possible service to our travelers and tenants — this is a necessary upgrade,” said SEA Airport Managing Director Wendy Reiter. “As we’ve done in previous Upgrade SEA projects, we’re being innovative by building up and not out. We’re mindful of the fact that we have one of the smallest footprints of any major U.S. airport considering our passenger volume.”
“The design solution for the S Concourse Evolution project carefully balances required resiliency improvements to the existing structure and systems, increased efficiency for aircraft operations and building services, and modernization of the interior to enrich the traveler experience,” said Kevin Keady, AECOM West Region Business Leader of Buildings + Places. “The design is inspired by local, indigenous concepts combined with pragmatic enhancements that will achieve greatly improved passenger service levels and meet the high standards travelers are accustomed to at one of the world's busiest airports. We are grateful for the opportunity to work with SEA airport on this exciting project that will benefit the region for the next 50 years.”
How will they do it
The project will be completed in multiple phases over the course of eight years. This allows continuous flight operations at most gates during construction and minimizes traveler and airline operational impacts.
To make up for the gate closures, a temporary S Annex east of the facility will be built to support ground boarding operations. The goal is to have only three of the 12 gates impacted by construction at any time. As each phase of the project is completed, more space will reopen to the public, with all phases currently estimated to be completed by 2034.
Check out our latest video for a glimpse of what’s to come
Sustainable stewardship
This project is aiming for LEED Silver certification once completed, and it will incorporate various sustainable design strategies resulting in an anticipated 58% reduction of annual operational greenhouse gas emissions and 16% reduction of annual energy use from Port Standard. Significant components include:
- Exterior enclosure and high-performance glazing
- Enhanced lighting and building management systems
- Electrical equipment in lieu of fossil fuel
- Low-flow plumbing fixtures
- Electric vehicle (EV) charging for aircraft service equipment
- Reuse of building material
Upgrade SEA progress
Here’s a quick list of completed Upgrade SEA projects and what’s still to come:
- N Concourse Modernization — Complete (2021)
- International Arrivals Facility — Complete (2022)
- Restroom Renovation — Complete (2025)
- SEA Gateway Project — Complete (2026)
- C Concourse Expansion — Complete (2026)
- Roadway Improvements — Nearing completion this fall
- Baggage Optimization — In progress (completion by 2029)
- SEA Underground Controls Replacement — In progress (completion by 2027)
Estimated project costs
The total estimated project cost for the SCE is $2.5 billion. Today’s Commission authorization is for $1.1 billion to fund the project into 2029. The remaining costs will be presented to the Commissioners for their review and consent at a later date. Funding for the project comes from a combination of Airport Development Fund and future revenue bonds. As with virtually all airport projects, no taxpayer dollars will be used to fund the project.
