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

Almost all international flights from the US arrive at Incheon (ICN). Gimpo is primarily used for domestic flights or very specific short-haul regional routes.

What is the best day of the week to fly?

Tuesday and Wednesday are consistently the cheapest days to fly across the Pacific, while Fridays and Sundays are the most expensive.

Should I book with a third-party site to save money?

No. Always book directly with the airline. If there is a cancellation or delay, third-party sites make it nearly impossible to get help, whereas airlines will deal with you directly.

Finding cheap flights to Seoul from the US

To get the best price, book your flight exactly 4 to 6 months in advance using Google Flights to track price drops. Avoid flying on weekends, and look for mid-week departures (Tuesday or Wednesday) to consistently save $200–$400 per ticket.

Set up price tracking alerts. Open Google Flights and enter your departure city and ICN as the destination. Toggle the 'Track prices' switch. You will receive an email whenever the price for your selected dates drops significantly.
Use the calendar view. Once you enter your origin and ICN, click on the date box. Use the 'Date grid' or 'Price graph' view. This shows you the cheapest days to fly for the entire month, rather than just the dates you originally guessed.
Consider alternate airports. If you are flying from a secondary US city, it is often cheaper to book a domestic flight to a major hub like LAX, SFO, or SEA, and then book a separate, longer-haul flight to Seoul (ICN). Check the price difference versus booking one single ticket.
Check budget carriers. Look at airlines like Air Premia, which is a hybrid carrier that often offers lower prices than legacy airlines like Korean Air or Asiana, while still including more amenities than traditional budget airlines.

Is it cheaper to fly into Gimpo (GMP) or Incheon (ICN)?: Almost all international flights from the US arrive at Incheon (ICN). Gimpo is primarily used for domestic flights or very specific short-haul regional routes.
What is the best day of the week to fly?: Tuesday and Wednesday are consistently the cheapest days to fly across the Pacific, while Fridays and Sundays are the most expensive.
Should I book with a third-party site to save money?: No. Always book directly with the airline. If there is a cancellation or delay, third-party sites make it nearly impossible to get help, whereas airlines will deal with you directly.