United Airlines is making some big changes at 
Seattle-Tacoma International Airport (SEA). The airline is relocating its entire operation to a new concourse, meaning a new lounge will be on the way as well.
The United gates will be relocated from Concourse A to Concourse B at SeaTac, and a new United Club is expected to be built in the new terminal spaces. The project first began in 2021.
United’s Change Up At SeaTac
Photo: MC MEDIASTUDIO | Shutterstock
The construction of United’s new home at SeaTac has been estimated at over $100 million USD. The airport authority is responsible for the move and is paying for the cost of the changes for United, according to a report by View From The Wing. The current United Club at gate A9 will be transferred to 
Delta Air Lines as part of the concourse changes.
United has been at the North Concourse A for over 40 years. As King 5 News recounts, the new spaces will be on the south end of the airport. Delta will be taking over the Concourse A gates with plans for international flights, which those gates are made to accommodate. Delta is currently the second-largest carrier at SeaTac and has a much bigger share of traffic than United.
The Port of Seattle program describes the project as:
“To accommodate the opening of the International Arrivals Facility, this project will relocate United Airlines, a domestic only carrier at SEA, to Concourse B and move Delta Air Lines, a carrier with international flights at SEA, from Concourse B into those vacated gates and spaces on Concourse A.”
The A9 United Club
Photo: kamilpetran | Shutterstock
The current lounge for United flyers at SeaTac was opened in 2013. The 6,096-square-foot lounge offers picturesque views of the Cascades Mountains. The club features a bar, workstations, power outlets, free WiFi, and snacks. At that time, the new lounge was part of a consolidation of the Concourse A gates that eliminated the need to take the train after check-in to get to the boarding area.
In 2013, United was one of the largest carriers at SeaTac. The airline also had international service with a transpacific flight route to 
Tokyo Narita Airport (NRT). As competition with Delta and Alaska intensified, United began to pull back on its operations just one year later. The carrier closed both its pilot and flight attendant bases at SeaTac in 2014. Delta ramped up its presence and essentially pushed United out.
According to a USA Today report from the time, Delta increased both its domestic and international capacity between 2012 and 2014. The investment by Delta saw United lose passengers at almost 10% per year, even relinquishing its rights to the Tokyo route. Delta would fly to both Narita (NRT) and Haneda (HND). The 
Star Alliance member All Nippon Airways (ANA) also took some of the capacity that United surrendered.
The Gateway To The Pacific Northwest
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Alaska Airlines is the dominant carrier at SeaTac, accounting for around half of all traffic in and out of the busiest hub in the PNW. Delta is also strong, sharing about 20% of the capacity, which leaves little room for another member of the “Big Three” US airlines to make a profit flying to SEA. United has shifted its priorities elsewhere, and in 2025, it has the largest commercial fleet of aircraft in the world, with over 1,000 jets.
The Port of Seattle began construction to expand the airport a few years ago, and the post-pandemic resurgence of air travel has challenged the legacy infrastructure. SeaTac has over 50 million flyers a year passing through its gates. Part of the project will be to consolidate Alaska Airlines’ growing business to be the only airline operating on the north side of the airfield.
United Airlines
IATA CodeUA
ICAO CodeUAL
Airline TypeFull Service Carrier
Hub(s)Chicago O’Hare International Airport, Denver International Airport, Guam International Airport, Houston George Bush Intercontinental Airport, Los Angeles International Airport, Newark Liberty International Airport, San Francisco International Airport, Washington Dulles International Airport
Year Founded1931
AllianceStar Alliance
CEOScott Kirby
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Alaska merged with Hawaiian Airlines in 2024 under a nearly $2 billion USD deal. The acquisition brought Airbus A330 and 
Boeing 787 Dreamliners into the combined fleet that are expected to add transpacific capacity to SeaTac. The jets are likely to fly both domestic and international long-haul as Alaska is on track for growth.