Sea-Tac Airport moves closer to a new terminal

Seattle-Tacoma International Airport is one step closer to opening a new terminal, part of the airport’s master plan to accommodate millions of passengers moving through the crowded airfield.

The Federal Aviation Administration last month approved 31 projects at Sea-Tac to help the airport keep up with an expected uptick in demand. Those projects include the new terminal, extended taxiways, new cargo warehouses, a parking lot for airport employees and a fuel storage facility.

The new terminal, planned just north of the existing one, would add up to 19 gates to the 89-gate airport. Sea-Tac’s plan also includes an automated people mover,” like a train or shuttle, or even autonomous vehicles, to connect the new terminal with the main terminal and rental car facility.

In an environmental review, the FAA determined the projects would not significantly affect the “quality of the human environment,” paving the way for Sea-Tac to move to the next step in the lengthy process.

The Port of Seattle will next lead the state’s environmental review, with a public comment period expected in early 2026 and a decision later in the year. Then the elected Port Commission would need to approve each of the proposals.

The Port expects all 31 projects will be complete or underway by 2032.

Sea-Tac is “proposing to expand … to meet the demand we have today and that we know is coming in the next few years,” the Port said in a news release. “These investments would help us maintain a functioning and welcoming airport.”

Sea-Tac has been considering ways to improve the passenger experience since 2015, when it created a master plan meant to address the rising demand.

If the airport did not increase its existing capacity, and demand increased as expected, flights would be delayed an average of 20 to 25 minutes by 2029 and more than 40 minutes by 2034, according to a summary of the master plan.

The new terminal, and other projects pending approval right now, are part of Sea-Tac’s near-term vision but won’t ultimately fix the growing overcrowding problem. Port of Seattle officials say they’ll eventually need a larger footprint and, ultimately, a new regional airport.

That airport’s location is a contentious issue in the region. After ferocious backlash from communities shortlisted for a new airport site, Washington officials in 2023 walked back plans for selecting a site, without putting a new mandate in place.

The Seattle area has struggled to satisfy air travel demand for more than a decade. In 2008, when Sea-Tac opened a third runway to add capacity for 150,000 more flights a year, an aviation planning council was already discussing the need for a fourth runway.

Sea-Tac has made incremental changes to keep up with immediate demand increases, including a $5 billion, multiyear series of upgrades that introduced new checkpoints to modernize baggage handling, new restrooms and wider access roads. Those renovations, collectively called Upgrade SEA, are expected to be complete by July 2026, in time for Seattle to host World Cup soccer matches.

Recognizing it would need to conduct a comprehensive study to tackle the long-term issue, Sea-Tac carved out 31 smaller projects from its master plan to start winding through the approval process and preparing the airport to keep up with immediate demand increases.

Together, the pending projects should allow Sea-Tac to accommodate an estimated 56 million annual passengers, according to the FAA’s review.

They will also help the airport meet cargo demand, improve the efficiency of taxiways, bring airport infrastructure up to date with FAA standards and help Sea-Tac incorporate lower-emission aviation fuel.

In its review, the FAA noted 17 findings the Port must address when designing, building and operating the proposed facilities. The Port said all but one of those findings are “common business practices” at Sea-Tac.

The remaining finding is a request from the FAA to make surface improvements at 26 intersections in the surrounding communities, a roughly $40 million investment, according to the Port.

The environmental review for the proposed projects is expected to cost $6.4 million, the Port said on its website. That money will come from “airport development funds, or the money Sea-Tac earns from things like parking garage fees and a percentage of dining and retail fees.