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

Return flights

03 Dec - 10 Dec	Korean Air
25 Dec - 15 Jan	Alaska Airlines
04 Dec - 13 Dec	Korean Air
06 Dec - 13 Dec	Korean Air
10 Dec - 16 Jan	Alaska Airlines
06 Dec - 11 Dec	Korean Air
08 Dec - 16 Dec	Korean Air
07 Dec - 09 Dec	Korean Air
06 Dec - 20 Jan	Korean Air
24 Dec - 19 Jan	Alaska Airlines
08 Dec - 15 Dec	Korean Air
06 Dec - 12 Dec	Korean Air
05 Dec - 15 Dec	Korean Air
02 Dec - 25 Dec	Korean Air
26 Dec - 10 Jan	Alaska Airlines
25 Dec - 17 Jan	Alaska Airlines
10 Dec - 10 Jan	Alaska Airlines
30 Dec - 08 Jan	Alaska Airlines
26 Dec - 09 Jan	Alaska Airlines
25 Dec - 01 Jan	Hawaiian Airlines

Also check the deals for one-way flights from San Jose 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 San Jose to Seoul in December from $833

Return flights