Seattle-Tacoma Airport begins $2.5bn S Concourse modernisation

Seattle-Tacoma International Airport is advancing a $2.5 billion transformation of its S Concourse, adding space, amenities and more efficient operations while using a phased approach to minimise disruption for travellers and airlines.

Summary:

Seattle-Tacoma International Airport is advancing a $2.5 billion transformation of its S Concourse, with major construction scheduled to begin in 2027.
The S Concourse Evolution project will add 150,000 square feet, including a new upper concourse level, improved boarding operations and expanded dining, retail, lounge and passenger amenities.
The eight-year project is designed to maintain airport operations during construction, using phased delivery and a temporary S Annex to minimise impacts on travellers and airlines.

The Port of Seattle Commission has authorised initial funding for the next significant modernisation project at Seattle-Tacoma International Airport (SEA) – a Corporate Partner of the FTE Digital, Innovation & Startup Hub. Major construction on the S Concourse Evolution (SCE) is scheduled to start in 2027. As part of the $5.5 billion Upgrade SEA capital improvement programme, the estimated $2.5 billion S Concourse renovation will transform a 1973 facility into a world-class concourse that primarily serves international travellers. The project matches recent SEA modernisation project standards, ensuring increasing traveller demands are met with more space, amenities, and sustainability, including reduced energy use and greenhouse gas emissions.

“Today’s authorisation 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 modernisation 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 travellers 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 project will be completed in multiple phases over the course of eight years. This allows continuous flight operations at most gates during construction and minimises 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.

“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 modernisation of the interior to enrich the traveller 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 travellers 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.”

Hear more from Seattle-Tacoma International Airport at the 20^th anniversary edition of FTE Global, taking place in Dallas, Texas, on 8 to 10 September 2026. Wendy Reiter, Managing Director, Seattle-Tacoma International Airport, is moderating a session titled ‘The checkpoint has changed: How TSA Gold+ and next-generation technology are redefining airport security right now’.

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