Incheon International Airport: A Traveler's Guide
Incheon (ICN) is consistently ranked among the world's best airports, and it's built to handle a stopover as easily as a straight-through trip. There are two terminals — Terminal 1 (mostly Asiana, Star Alliance-affiliated and many foreign carriers) and Terminal 2 (Korean Air, Delta, and SkyTeam partners) — linked by a free shuttle train that takes about 15-18 minutes, so check which terminal your flight uses before you plan your time.
Arrival basics. All foreign nationals complete an e-Arrival Card (fill it in online before you fly to save time) and have fingerprints and a photo taken at immigration. Lines move briskly outside of the evening arrival peak. Customs uses a standard declare/nothing-to-declare split. If you have a long layover, Incheon runs free transit tours (a few hours, covering nearby sights or even central Seoul) for eligible connecting passengers — worth checking at the transfer desk if you have 5+ hours between flights.
Getting into the city. The AREX airport railway is the standard route: the non-stop express train reaches Seoul Station in about 43 minutes from Terminal 1 for roughly 13,000 KRW, while the all-stop local train takes closer to an hour but costs only about 5,000 KRW. From Seoul Station you can transfer onto the subway network. Taxis take 60-70 minutes to central Seoul depending on traffic and typically run 55,000-80,000 KRW on the meter (more for a deluxe or international taxi). Airport limousine buses are a comfortable middle option, dropping at major hotels and neighborhoods for around 10,000-18,000 KRW.
Practical tips. Pocket Wi-Fi and SIM/eSIM rental counters are just past arrivals in both terminals and are genuinely fast to use — worth doing even for a short trip, since Korea's mobile data speeds are excellent. Won cash is easy to get from arrivals-hall ATMs, though cards (including foreign ones) are accepted almost everywhere in Seoul. Minimum connection times are officially 60 minutes for domestic-to-domestic and closer to 90 minutes minimum for international connections requiring a terminal change — if you're on separate tickets, treat 2+ hours as your real safety margin given the T1-T2 shuttle and security requeue.