August 13, 2026

Lift off! Sea-Tac S Concourse revamp to start next year

Rendering courtesy AECOM and HOK [enlarge]

AECOM says the modernization design “is inspired by local, indigenous concepts combined with pragmatic enhancements.”

The Port of Seattle Commission on Tuesday authorized $1.1 billion in funding for its long-planned modernization of the S Concourse at Seattle-Tacoma International Airport. The money will fund the multi-phase project into 2029.

The S Concourse was built in 1973 and mainly serves international travelers. The approximately 350,000-square-foot satellite terminal has seven levels and 12 gates. The port says it has only received minimal updates since the 1980s.

Through renovations and new construction, the modernization will restructure and repurpose existing space, including part of a customs area vacated when the International Arrivals Facility opened in 2022, to increase operational efficiency, meet code requirements and enhance passenger experience. The project will add 150,000 square feet of space for passengers, including a new upper concourse level, improved dual-level boarding operations for select gates, plus expanded dining, retail, lounge, and passenger amenities.

The project does not increase gate count on the concourse, as there is no room to expand between the main terminal and the airfield.

Structural, seismic and building systems will be overhauled to ensure the concourse can continue to operate and serve passengers for another 50 years, the port says. The project will also bring the concourse into compliance with the airport's high sustainably standards and is targeting LEED Silver certification.

MULTI-PHASED APPROACH

Screengrab from Port of Seattle video [enlarge]

The S Concourse has 12 gates and can accommodate 13 widebody aircraft, or 18 narrowbody aircraft.

With the first pool of funding secured, the port says major construction is scheduled to start in 2027. The entire build-out is anticipated to take eight years. The multi-phase approach will allow for continuous flight operations at most gates during construction and minimize traveler and airline operational impacts. The port's goal is to have only three of the 12 gates impacted by construction at any time. To make up for gate closures, a temporary S Annex east of the facility will be built to support ground boarding operations. As each phase of the project is completed, more upgraded space will reopen to the public.

AECOM is the prime consultant and lead architect on the project, and HOK is the lead designer. Hensel Phelps is the general contractor.

SUSTAINABLE DESIGN

Kevin Keady, AECOM West region business leader of buildings and places, said in a press release that the design “is inspired by local, indigenous concepts combined with pragmatic enhancements.”

Sustainable design strategies are expected to result in a 58% reduction of annual operational greenhouse gas emissions and a 16% reduction of annual energy use from the port standard. Sustainable elements include high-performance glazing, enhanced lighting and building management systems, electrical equipment in lieu of fossil fuel, low-flow plumbing fixtures and electric vehicle charging for aircraft service equipment. Existing building materials will be reused during construction.

All phases are currently estimated to be completed by 2034. The remaining costs for the project will be presented to port 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.

The renovation is part of the $5.5 billion Upgrade SEA capital improvement program announced in 2022, which also includes the new C Concourse that opened in June.

The C Concourse and evolution of the S Concourse exemplify how the airport is employing innovative design solutions to upgrade its facilities within existing space constraints. The former built four new floors and over 145,000 square feet of space atop an existing concourse building.