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

Return flights

31 Dec - 28 Jan	Hainan Airlines
29 Dec - 24 Jan	Frontier Airlines
30 Dec - 14 Jan	Frontier Airlines
29 Dec - 13 Jan	Porter Airlines (Canada) Ltd
24 Dec - 14 Jan	Spirit Airlines
29 Dec - 09 Jan	Cathay Pacific
24 Dec - 06 Jan	Spirit Airlines
24 Dec - 31 Dec	SWISS
23 Dec - 30 Dec	WestJet
30 Dec - 20 Jan	Delta	direct
31 Dec - 28 Jan	Delta	direct
23 Dec - 28 Dec	Cathay Pacific
29 Dec - 24 Jan	Delta	direct
23 Dec - 30 Dec	Korean Air	direct
23 Dec - 28 Dec	Korean Air	direct
22 Dec - 29 Dec	Delta	direct

Also check the deals for one-way flights from Boston 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 Boston to Seoul in December from 798€

Return flights