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Guide to Seattle–Tacoma International Airport (SEA)

Also known under the names SEA Airport and Sea-Tac, Seattle-Tacoma International Airport (SEA) is a commercial airport serving the greater Seattle area. It is located with the city limits of SeaTac, a small recently incorporated (1990) city of about 10 square miles and a population of just under 30,000.

Roughly equidistant from the cities of Seattle (14 miles) and Tacoma (18 miles), Sea-Tac is also within easy reach of the major cities of Oregon, Portland and Vancouver B.C.

Relatively small for the volume of traffic at just 2,500 acres, Seattle-Tacoma operates domestic and international flights and is a primary hub for major operator Alaska Airlines. Delta Air Lines also has a major presence at the airport and, in 2022, there were 31 airline companies operating at Seattle-Tacoma Airport running flights to 91 domestic and 28 international airports.

The airport was built on a new site near the already existing Boeing Field which was under military control. Under construction since 1944, Sea-Tac was officially opened in 1947 with the first scheduled flights by Trans-Canada and Northwest arriving in the same year. More airlines moved operations from Boeing Field to Sea-Tac in the following years as Trans-Canada and Northwest were joined by Western Airlines, United Airlines and Pan Am.

By mid-1957, there mere more than 200 flight departures per week to domestic and international destinations and the first non-stop flights to Europe by Pan Am began in 1961.

Major Expansion Work

By the late sixties, with Seattle-Tacoma taking more business from Boeing Field and demand for flights continually increasing, the airport was soon struggling to cope and major expansion was required. Between 1967 and 1973, a new runway was added as well as two purpose-built satellite terminals. Elsewhere at the airport an underground train was installed, a parking garage built and passenger facilities updated and improved.

Further redevelopments and improvements took place through the eighties as the Main Terminal was extended and renovated, Concourse D expanded and Concourses B, C and D received major overhauls with new gates and moving sidewalks added.

As Seattle-Tacoma continued to expand its business further improvements were required. The main terminal building was expanded and renovated in 2003, a new control tower opened in 2004 and a third runway added in 2008.

In recent years, Delta Air Lines has significantly increased its operations at Sea-Tac and has added dozens of domestic and international flights to its roster and, in 2021, American Airlines set about making Seattle-Tacoma Airport a hub for flights to Asia.

Simple X Layout

The Central Terminal at Seattle Airport is basically shaped like an X with each of the four concourses located on its own leg of the X. Departure and arrival areas are designated as Concourses A to D and there are also two satellite terminals labelled North and South.

The Central Terminal is a multi-level complex. Level 2 is where the airport's Satellite Transit System (STS) is located with Baggage Claim on Level 3.

Once through security it is possible to walk between terminals and concourses and there is also an automated people mover system in place, the SEA Underground. For longer distances, or for ease of travel, passengers can also take the STS Blue, Yellow or Green lines between the different arrival and departure points.

STS Between Terminals

The airport's automated people mover system, the Satellite Transit System, operates three colour-coded lines between concourses and the satellite terminals.

  • Blue Line runs between Concourses A, B and South Satellite Terminal
  • Green Line runs between Concourses C, D and North Satellite Terminal
  • Yellow Line runs from Concourse A to D

Which terminal or concourse is required will depend on the airline and the destination. The usual airline allocated arrival and departure points are as follows (subject to changes):

Concourse A (16 Gates)

Air Canada, Aer Lingus, JetBlue, Delta Air Lines, United Airlines, Japan Airlines

Concourse B (17 Gates)

Frontier Airlines, Southwest Airlines, Aer Lingus

Concourse C (27 Gates)

Alaska Airlines

Concourse D (17 Gates)

American Airlines

North Satellite (20 Gates)

United Airlines, Alaska Airlines

South Satellite (14 Gates)

Air France, AeroMexico, All Nippon Airways, Asiana Airlines, Condor, British Airways, Eurowings, Emirates, EVA Air, Hawaiian Airlines, IcelandAir, Lufthansa, Korean Air, Qatar Airways, Volaris, Virgin Atlantic, Xiamen Airlines

The vast majority of international arrivals will disembark in the South Satellite Terminal although pre-cleared passengers will be processed in one of the other arrivals areas.

Immigration and Customs

Despite improvements at Seattle-Tacoma Airport in recent years it can still take up to an hour for arriving international passengers to clear security and customs checks and even longer during peak hours. Pre-cleared passengers using an ESTA approved passport are generally processed through the airport faster than non-nationals with U.S. Visas and Customs Declaration Forms which need to be checked.

Pre-cleared Passengers

Citizens of Visa Waiver Program (VWP) countries no longer need a visa to enter the United States. Instead, an ESTA (Electronic System for Travel Authorization) is required. This works the same as a visa but is in electronic form and linked to a passport. Having completed a detailed questionnaire and undergone stringent background checks, intending visitors to America will be granted or denied an ESTA without which it is impossible to enter the United States. The VWP list of countries includes: Andorra, Australia, Austria, Belgium, Brunei, Chile, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Japan, Latvia, Liechtenstein, Lithuania, Luxembourg, Monaco, Netherlands, New Zealand, Norway, Poland, Portugal, Republic of Malta, San Marino, Singapore, Slovakia, Slovenia, South Korea, Spain, Sweden, Switzerland, Taiwan, United Kingdom.

Non-Cleared Passengers

Arriving non-American citizens who are not eligible for an ESTA must be in possession of a valid passport and a U.S. Visa. They are also required to complete a Customs Declaration Form detailing any items on the banned list they may have on their person or in their baggage. Queues for non-nationals using a visa tend to be longer and slower moving than those for pre-cleared arrivals as all documentation is closely scrutinised by the Customs and Border Protection (CBP) agents on duty and baggage is more likely to be hand checked for this group of people.

Global Entry Program

Clearing security and customs at Seattle-Tacoma International, or any participating airport, can be expedited using the Global Entry Program. Global Entry is primarily designed for frequent travelers who enter or exit the U.S.A. on a regular basis.

Enrolment in the scheme is done through completing a detailed questionnaire, supplying fingerprint impressions and undergoing a background check. Membership is open to American citizens or residents as well as citizens of countries on a list of approved countries deemed to be a low security risk. The list includes the following countries: Andorra, Australia, Austria, Belgium, Brunei, Chile, Croatia, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Japan, Latvia, Liechtenstein, Lithuania, Luxembourg, Monaco, Netherlands, New Zealand, Norway, Poland, Portugal, Republic of Malta, San Marino, Singapore, Slovakia, Slovenia, South Korea, Spain, Sweden, Switzerland, Taiwan, United Kingdom.

Once accepted into the program, a member's details and fingerprints are stored in a secure database and can be quickly retrieved at Global Entry kiosks in the airport and the resulting receipt validated by immigration and customs officials.

Global Entry kiosks are located in the airport's Central Terminal alongside five security checkpoints.

Transfers and Ground Transportation

The usual travel options for getting to and from an airport can be found at Seattle-Tacoma with the welcome addition of a light rail service.

Light Rail

Running from the airport's own station (located in the parking garage beside the Central Terminal) to the University of Washington, the Link Light Rail has regular departures every 6 to 15 minutes.


Sound Transit Bus - Operates regular services to and from the airport. Express buses operated by Sound Transit Bus to Lakewood, Tacoma, Bellevue and Renton run from the southern end of the Central Terminal.

King County Metro Bus - Passengers can walk to the bus station on International Boulevard using the Skybridge and choose between various destinations covered by Routes 180, 156 and the Rapid Ride A line.



Booked in advance or arranged upon arrival, there are a number of private and shared-ride shuttles to be found at Seattle-Tacoma and some local hotels also operate courtesy services.


The taxi rank is located at the airport parking garage.

Ride Sharing

Approved ride-share services Uber, Lyft and Wingz all operate services to and from the airport with drop-off points outside the departure and arrivals areas.