Incheon International Airport opened on March 29, 2001, replacing Gimpo International Airport as South Korea's primary international gateway. Construction began in November 1992 with the building of a seawall and the reclamation of the shallow tidal flat between Yeongjong and Yongyu Islands in the Yellow Sea, the largest civil engineering project in Korean history. The airport is connected to the South Korean mainland via the Yeongjong Bridge and sits roughly 48 km west of Seoul.

From the start, the airport was designed to anchor Northeast Asian aviation. It succeeds on that ambition. Korean Air and Asiana Airlines use it as their primary hub, and the airport's top international routes run to Tokyo, Osaka, Fukuoka, Bangkok, and Hong Kong. A third runway and midfield satellite concourse opened in June 2008 during Phase 2 expansion. Terminal 2 followed in January 2018, dedicated to Korean Air and its SkyTeam partners, while most other international carriers operate from Terminal 1. A fourth runway came online in June 2021 as part of a fourth-phase expansion that brought annual capacity to 106 million passengers. The airport recorded 74.07 million passengers in 2025.

ICN earned the ACI Airport Service Quality award for Best Airport Worldwide for 12 consecutive years. In 2022 it became the first airport in the world to achieve Level 5 status in ACI's Airport Customer Experience Accreditation programme. Within 3.5 hours' flying time, the airport can reach 51 cities with populations exceeding 1 million, a geographic position that makes it one of the most strategically located hubs on the planet.