Incheon International Airport (ICN): Incheon Airport is the primary international gateway to Seoul. It is one of the busiest airports in the world and serves numerous airlines from around the globe. Many major cities have direct flights to Incheon Airport.
Gimpo International Airport (GMP): Gimpo Airport mainly handles domestic flights and some regional flights from nearby countries. If you are flying from within South Korea or neighboring countries, you may arrive at Gimpo Airport.
By Train
Seoul is well-connected to neighboring countries through an extensive train network. However, direct international trains are limited. One notable exception is the KTX (Korea Train Express) service between Seoul and Beijing, China.