Is it cheaper to fly into Gimpo (GMP) or Incheon (ICN)?

Almost all international flights from the US land at Incheon (ICN). Gimpo is primarily for domestic or short-haul regional flights (like Tokyo or Beijing).

Are 'hidden city' tickets safe for Seoul?

No. Airlines are very strict about itineraries involving international hubs. It is not worth the risk of having your ticket canceled for skipping a segment.

Finding Cheap Flights from the USA to Seoul

To get the best price, book your flights 3 to 5 months in advance and prioritize flights arriving at Incheon International Airport (ICN). Use Google Flights to track prices and set alerts for your specific travel dates to capture price drops.

Set up tracking early. Use Google Flights to search for your route (e.g., LAX to ICN). Toggle the 'Track Prices' switch on. You will get email alerts when the fare drops, which usually happens in 24-48 hour windows.
Check alternative airports. If you live in a secondary city, compare the cost of a long-haul flight from a major hub like LAX, SFO, or SEA. It is often cheaper to buy a separate domestic flight to a west coast hub and then a separate ticket to Seoul.
Leverage mid-week travel. Fly on a Tuesday or Wednesday. Avoid Friday and Sunday departures, which are consistently 15-20% more expensive due to weekend demand.
Evaluate budget carriers. Check airlines like Air Premia or ZIPAIR (via Tokyo). They offer 'hybrid' service—lower costs than legacy carriers like Korean Air or Asiana, but more comfort than traditional budget airlines.

Is it cheaper to fly into Gimpo (GMP) or Incheon (ICN)?: Almost all international flights from the US land at Incheon (ICN). Gimpo is primarily for domestic or short-haul regional flights (like Tokyo or Beijing).
Are 'hidden city' tickets safe for Seoul?: No. Airlines are very strict about itineraries involving international hubs. It is not worth the risk of having your ticket canceled for skipping a segment.