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

Return flights

02 Dec - 09 Dec	Austrian Airlines
01 Dec - 08 Dec	Lufthansa
02 Dec - 11 Dec	SWISS
05 Dec - 07 Dec	TAP
04 Dec - 09 Dec	Lufthansa
01 Dec - 04 Dec	Lufthansa
03 Dec - 09 Dec	Lufthansa
04 Dec - 07 Dec	Lufthansa
03 Dec - 07 Dec	Austrian Airlines
04 Dec - 08 Dec	Lufthansa
12 Dec - 10 Jan	Aer Lingus
29 Dec - 18 Jan	Air Canada
30 Dec - 11 Jan	Aer Lingus
13 Dec - 20 Jan	Austrian Airlines
31 Dec - 24 Jan	Aer Lingus
12 Dec - 12 Jan	Aer Lingus
15 Dec - 20 Jan	Air Canada
15 Dec - 09 Jan	Lufthansa
15 Dec - 17 Jan	Austrian Airlines
30 Dec - 11 Jan	Virgin Atlantic	direct

Also check the deals for one-way flights from Boston to London 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 London in December from 382€

Return flights