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

Return flights

01 Dec - 12 Dec	Air Canada
29 Dec - 21 Jan	Air Canada
28 Dec - 04 Jan	Air Canada
12 Dec - 19 Dec	Air Canada
22 Dec - 24 Dec	Asiana Airlines
22 Dec - 24 Dec	Asiana Airlines	direct
29 Dec - 21 Jan	Asiana Airlines	direct
15 Dec - 22 Dec	Asiana Airlines	direct
15 Dec - 20 Jan	Asiana Airlines	direct
01 Dec - 12 Dec	Delta	direct
23 Dec - 31 Dec	Air Canada
12 Dec - 19 Dec	Delta	direct
19 Dec - 30 Dec	Air Canada
19 Dec - 30 Dec	Asiana Airlines	direct
27 Dec - 03 Jan	Turkish Airlines
28 Dec - 04 Jan	Korean Air	direct
20 Dec - 04 Jan	Air Canada
20 Dec - 03 Jan	Alaska Airlines
27 Dec - 03 Jan	Hawaiian Airlines	direct
20 Dec - 04 Jan	Hawaiian Airlines	direct

Also check the deals for one-way flights from Seattle 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 Seattle to Seoul in December from $874

Return flights