Almost all international flights to Seoul land at Incheon Airport. Incheon is a city an ~hour west of Seoul, but getting to Seoul from the airport is straightforward. If your flight lands in Incheon, continue here:
open_in_new Getting to Seoul from Incheon Airport (ICN)
Some shorter flights to Seoul (especially from east asia) land at Gimpo Airport. If your flight lands in Gimpo, continue here:
