Seattle Tacoma Airport Guide: Alaska’s Home, Delta’s Pacific Door
Seattle Tacoma Airport explained: three parallel runways, the Alaska and Delta hubs, the satellites, light rail access and the new terminal plan.
By The Aviation Hub
7 min read
Updated October 20, 2026 
Seattle Tacoma Airport is the air gateway to the Pacific Northwest and the busiest airport between San Francisco and the Canadian border. It occupies a plateau in the city of SeaTac, south of Seattle and north of Tacoma, and handled a record 52.7 million passengers in 2025. Alaska Airlines calls it home, Delta has built a transpacific hub here, and Boeing’s factories sit a short drive away. For spotters it is a reliable place to see 737s by the hundred and a steady flow of wide bodies bound for Asia.
Seattle Tacoma Airport at a Glance
Seattle Tacoma Airport carries the IATA code SEA and the ICAO code KSEA. It lies about 14 miles (23 km) south of downtown Seattle and 18 miles (29 km) north of Tacoma, at an elevation of 433 ft (132 m). Three near parallel runways serve a single Central Terminal with four concourses and two satellites, plus the International Arrivals Facility that opened in 2022.
Traffic reached around 52.7 million passengers in 2025, up from roughly 50.9 million in 2023. Alaska Airlines carries about half of them and Delta roughly a quarter. The Port of Seattle, a public body governed by elected commissioners, owns and operates the field. Flight status, parking and terminal maps are on the airport’s official website.
How the Sea Tac Site Came to Be
The Second World War created the airport. When the military took over Boeing Field in 1942, the region needed a civil replacement, and the Port of Seattle picked a site near Bow Lake. Construction began in January 1943, and the first ceremonial landing came on 31 October 1944. Scheduled flights started on 1 September 1947, and the terminal was dedicated in July 1949. Sandy soil pushed the cost from an estimated 1.7 million dollars to more than 4.2 million.
Tacoma contributed 100,000 dollars to the project and earned the second half of the name in return. The city has defended it since. When the Port renamed the airport after Senator Henry M. Jackson in 1983, Tacoma residents voted four to one against the change in an advisory referendum, and the commission reverted to the original name in February 1984. The city of SeaTac, incorporated around the airport, took its name from the airport’s nickname.
The jet age brought the two satellites and the underground train in the early 1970s. The Central Terminal was rebuilt and expanded in 2003. The third runway opened in November 2008 after years of legal fights and a bill of 1.1 billion dollars. The North Satellite reopened in June 2021 after a 550 million dollar modernisation, and the International Arrivals Facility followed in 2022.
Runways at Seattle Tacoma Airport
Three concrete runways run almost parallel on a north to south heading. Runway 16L/34R, the original main runway on the eastern side, is the longest at 3,627 m (11,901 ft). The centre runway, 16C/34C, measures 2,873 m (9,426 ft). The western runway, 16R/34L, is 2,591 m (8,500 ft) long and is the one that opened in 2008. All three are 46 m wide.
The third runway exists because the two older ones sit too close together for simultaneous instrument approaches in poor visibility, which is a frequent problem in a Puget Sound winter. With 16R/34L in use, Seattle Tacoma Airport can land aircraft on both outer runways in poor visibility while the centre runway handles departures. Southerly operations on the 16s are the norm because of the prevailing wind. Taxiway Tango, which runs parallel to the runways, has been mistaken for a runway often enough that the FAA issued an alert about it in 2009.
Terminals and Airlines
Everything starts in the Central Terminal, which houses the check in halls and six security checkpoints. Concourses A, B, C and D fan out from it, and the SEA Underground train links the North and South Satellites. Alaska Airlines fills Concourse C and the whole North Satellite with its Boeing 737 fleet and Horizon Air Embraer E175s, and it shares Concourse D with American and other domestic carriers.
Delta uses Concourse A and part of B, with United and Southwest alongside it on B. The South Satellite is the international pier, where Delta’s Airbus A350-900s and Boeing 767s mix with British Airways, Lufthansa, Korean Air, EVA Air, Japan Airlines and Emirates. The International Arrivals Facility east of Concourse A connects to the satellite by a long aerial walkway. Not everything went to plan, as four of its gates were built too narrow for the wide bodies they were meant to serve.
In alliance terms this is a Oneworld and SkyTeam airport. Alaska’s membership of Oneworld brought American, British Airways, Qantas and Japan Airlines closer, while Delta’s SkyTeam partners Korean Air and Air France KLM feed its hub. Alaska’s purchase of Hawaiian Airlines added Airbus A330s and Boeing 787s to the mix in 2024.
Routes and Destinations
Around 37 airlines serve roughly 96 domestic and 37 international destinations. Denver, Phoenix and Los Angeles are the busiest domestic routes, each carrying around 900,000 passengers a year, followed by Anchorage, San Francisco and Chicago O’Hare. Alaska’s network reaches every corner of its home state and the West Coast, and Delta adds the eastern hubs.
Across the Pacific, Taipei is the largest international market with more than 770,000 passengers a year, then Seoul Incheon and Vancouver. Delta flies to Tokyo, Seoul, Shanghai and Taipei, and Alaska has started its own wide body flying to Tokyo and Seoul. The longest routes are Singapore Airlines’ direct service and Emirates’ Dubai flight, each well over 7,000 miles (11,300 km). Summer brings extra Alaska flights to the interior and a heavy cruise season for Vancouver and Anchorage. Cargo is significant, with Asian freighters a regular sight.
Getting to and from Seattle Tacoma Airport
The Sound Transit 1 Line light rail stops at SeaTac/Airport station, a short covered walk from the terminal. Trains reach downtown Seattle in about 40 minutes and continue north to the University of Washington and Lynnwood, or south to Federal Way. The fare is a few dollars, which makes it the cheapest sensible way to reach Seattle Tacoma Airport. Tukwila station, 5 miles away, offers Sounder commuter trains and Amtrak Cascades.
By road, State Route 518 links the airport to Interstate 5 and Interstate 405, and the Airport Expressway feeds the terminal drives. Downtown is 20 to 30 minutes away outside the rush hour and considerably more during it. Taxis and ride hailing cost around 50 to 60 dollars to the city centre. King County Metro and Sound Transit buses serve the airport, and the parking garage with more than 12,000 spaces is said to be the largest under one roof in North America.
Spotting and Photography
Seattle Tacoma Airport is a friendly place to spot. The Central Terminal and Concourse A have large windows facing the runways, and the aerial walkway to the South Satellite gives a high view of the apron. Outside, the South 188th Street bridge over State Route 509 is the best spot for arrivals on 34L. Mathison Park off South 146th Street sits under the approach to 16R, and the roadside on South 146th Street also catches arrivals on 16L and 16C.
Light comes from the east in the morning, which suits the terminal windows, and swings west in the afternoon. The grey months bring low cloud and rain, so late spring and summer give the best conditions. Stay off the Port’s service roads, use the designated public areas, and keep clear of the perimeter fence on the western side where patrols are frequent.
What Comes Next
The Sustainable Airport Master Plan recommends more than 30 projects to cope with another million residents in the Puget Sound region by 2035. The centrepiece is a new terminal with 19 gates and an automated people mover. In the meantime, a four storey addition to Concourse C costing 399 million dollars is due in 2027, alongside a 320 million dollar baggage system upgrade.
Constraints are real. The airport is squeezed by the city around it, and noise and environmental objections slowed the third runway for a decade. Alaska’s growth after the Hawaiian deal and Delta’s transpacific ambitions will keep demand rising. Seattle Tacoma Airport is heading past 55 million passengers with no room for another runway, so the answer lies in bigger terminals and smarter scheduling. See how it compares with other US hubs on the Airports of the World map.
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