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

Return flights

21 Dec - 31 Jan	jetBlue
30 Dec - 07 Jan	LEVEL
20 Dec - 17 Jan	KLM
20 Dec - 18 Jan	KLM
24 Dec - 29 Dec	SWISS
24 Dec - 27 Dec	SWISS
27 Dec - 10 Jan	SWISS
23 Dec - 26 Dec	Frontier Airlines
28 Dec - 06 Jan	Lufthansa
23 Dec - 28 Dec	KLM
20 Dec - 27 Dec	KLM
25 Dec - 30 Dec	Frontier Airlines
31 Dec - 05 Jan	SWISS
21 Dec - 28 Dec	SWISS
22 Dec - 26 Dec	Azores Airlines
22 Dec - 29 Dec	Azores Airlines
22 Dec - 25 Dec	Azores Airlines
30 Dec - 05 Jan	LEVEL
27 Dec - 10 Jan	LEVEL	direct
31 Dec - 04 Jan	TAP

Also check the deals for one-way flights from Boston to Barcelona 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 Barcelona in December from 781€

Return flights