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

Return flights

09 Dec - 10 Dec	Iberia
07 Dec - 09 Dec	Air Canada
05 Dec - 07 Dec	Iberia
05 Dec - 09 Dec	TAP
07 Dec - 14 Dec	TAP
08 Dec - 14 Dec	TAP
01 Dec - 10 Dec	TAP
06 Dec - 08 Dec	Iberia
11 Dec - 16 Dec	Iberia	direct
03 Dec - 07 Dec	Iberia	direct
30 Dec - 24 Jan	Iberia	direct
31 Dec - 24 Jan	British Airways	direct
12 Dec - 10 Jan	British Airways	direct
11 Dec - 10 Jan	Iberia	direct
30 Dec - 11 Jan	Iberia	direct
07 Dec - 09 Jan	British Airways	direct
07 Dec - 10 Jan	British Airways	direct
14 Dec - 09 Jan	Icelandair
15 Dec - 13 Jan	Icelandair
13 Dec - 08 Jan	Icelandair

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 $361

Return flights