Seattle–Tacoma International Airport

The airport opened on 31 October 1944 following a 1943 groundbreaking, built by the Port of Seattle with federal Civil Aeronautics Administration funding after the site near Bow Lake was chosen over an alternative near Lake Sammamish.

The original 71,000-square-foot terminal, designed by Herman A. Moldenhour with a rooftop control tower and glass curtain walls, was dedicated on 9 July 1949 before 30,000 spectators, following the first scheduled commercial flights in September 1947.

Pan Am introduced the airport's first jet service on 3 October 1959, a Boeing 707 flight to Honolulu.

Northwest Orient Airlines Flight 305 was hijacked after departing Sea-Tac by a man using the alias 'Dan Cooper' (later misreported as 'D.B. Cooper'), who parachuted from the aircraft with $200,000 in ransom money; the case remains unsolved.

Two new satellite terminals connected by a pioneering automated underground shuttle-train system opened on 1 July 1973, among the first such systems in the United States.

An 8,500-foot third runway, costing $1.1 billion, opened on 20 November 2008 to enable low-visibility operations.

A 450,000-square-foot International Arrivals Facility, connected by a 900-foot elevated bridge, opened to support growing international traffic including Delta's transpacific hub established in 2014.

A cyberattack on 24 August 2024 disabled parts of the airport's digital infrastructure; most systems were restored by 31 August 2024.