Incheon International Airport opened on March 29, 2001, replacing Gimpo International Airport as South Korea's primary hub for international traffic. Construction began in November 1992 on reclaimed tidal land between Yeongjong and Yongyu Islands in the Yellow Sea, roughly 48 km west of Seoul. It took eight years to build and another six months of testing before the first flight departed. The project was originally scheduled for completion in 1997 but was delayed by the Asian financial crisis.

The airport sits within reach of 51 cities with populations exceeding 1 million within 3.5 hours' flying time, making its location one of the most advantageous in Northeast Asia for connecting long-haul routes between Europe, the Americas, and the Asia-Pacific. Korean Air, Asiana Airlines, Jeju Air, and Polar Air Cargo all use it as a primary hub. In 2024, the airport ranked 13th globally by passenger traffic and 6th by cargo volume. It holds 111 boarding gates across Terminal 1, Concourse A, and Terminal 2.

Terminal 2, designed by Heerim Architects & Planners with Gensler as collaborating design architect, opened on January 18, 2018, initially serving Korean Air and its SkyTeam partners including Delta Air Lines, Air France, and KLM. The terminals are linked by an underground Starline shuttle train. ICN held the top spot in the Airports Council International Airport Service Quality rankings for 12 consecutive years from 2005 to 2016, the only airport ever to achieve that streak. A fourth runway was added in June 2021, and a major Terminal 2 expansion completed in November 2024 brought total annual passenger capacity to over 100 million.