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

Return flights

23 Dec - 16 Jan	Korean Air	direct
24 Dec - 31 Dec	Turkish Airlines
25 Dec - 31 Dec	Turkish Airlines
13 Dec - 31 Dec	Turkish Airlines
12 Dec - 31 Dec	Turkish Airlines
30 Dec - 07 Jan	Delta
30 Dec - 07 Jan	Korean Air	direct
12 Dec - 03 Jan	Turkish Airlines
24 Dec - 31 Dec	Korean Air	direct
28 Dec - 03 Jan	Turkish Airlines
18 Dec - 01 Jan	Air Canada
12 Dec - 31 Dec	Korean Air	direct
28 Dec - 03 Jan	Korean Air	direct
18 Dec - 01 Jan	Delta	direct
20 Dec - 06 Jan	Turkish Airlines
12 Dec - 03 Jan	Korean Air	direct
13 Dec - 31 Dec	Korean Air	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.

Book a cheap hotel in Seoul

Cheap car rent in Seoul

Cheapest return flights from Seattle to Seoul in December from 743€

Return flights