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

Return flights

07 Dec - 15 Dec	Aer Lingus
11 Dec - 15 Dec	Aer Lingus
01 Dec - 08 Dec	Iberia For Level
05 Dec - 09 Dec	Aer Lingus
15 Dec - 23 Dec	Aer Lingus
04 Dec - 08 Dec	Scandinavian Airlines
11 Dec - 14 Dec	Aer Lingus
13 Dec - 19 Dec	Aer Lingus
11 Dec - 17 Dec	Air Canada
15 Dec - 10 Jan	Lufthansa
16 Dec - 17 Jan	Iberia
16 Dec - 10 Jan	Iberia
02 Dec - 06 Dec	TAP	direct
14 Dec - 06 Jan	SWISS
10 Dec - 06 Jan	SWISS
08 Dec - 06 Jan	SWISS
09 Dec - 06 Jan	SWISS
29 Dec - 06 Jan	Iberia For Level
24 Dec - 07 Jan	British Airways
14 Dec - 05 Jan	Scandinavian Airlines

Also check the deals for one-way flights from Boston to Lisbon 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 Lisbon in December from 362€

Return flights