AirHint found the following cheapest return flights from Washington (IAD) to Seoul (ICN) in December 2025 (see full year).

Return flights

31 Dec - 21 Jan	Saudia
31 Dec - 20 Jan	Saudia
26 Dec - 28 Dec	Frontier Airlines
31 Dec - 07 Jan	Air Canada
29 Dec - 31 Dec	Air Canada
29 Dec - 05 Jan	Frontier Airlines
29 Dec - 04 Jan	Frontier Airlines
24 Dec - 30 Dec	Air Canada
30 Dec - 01 Jan	Korean Air	direct
31 Dec - 21 Jan	Delta	direct
30 Dec - 06 Jan	KLM
29 Dec - 01 Jan	Korean Air	direct
29 Dec - 31 Dec	Korean Air	direct
27 Dec - 05 Jan	Ethiopian Airlines
24 Dec - 30 Dec	Korean Air	direct
26 Dec - 28 Dec	Korean Air	direct

Also check the deals for one-way flights from Washington to Seoul in December.

The deals are updated regularly. The prices may go up as tickets are purchased by other travellers. Only the cheapest flights are offered. Select a price to book and secure these cheap prices.

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Cheapest return flights from Washington to Seoul in December from $1234

Return flights