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

Return flights

07 Dec - 13 Dec	Air Canada
05 Dec - 06 Dec	Air Canada
09 Dec - 15 Dec	Air Canada
05 Dec - 07 Dec	Air Canada
02 Dec - 09 Dec	SWISS
07 Dec - 12 Dec	Icelandair
08 Dec - 12 Dec	Icelandair
13 Dec - 20 Jan	Icelandair
08 Dec - 13 Dec	SWISS
06 Dec - 13 Dec	Air Canada
10 Dec - 09 Jan	Icelandair
03 Dec - 10 Dec	Icelandair
09 Dec - 20 Jan	Icelandair
12 Dec - 08 Jan	Frontier Airlines
15 Dec - 16 Jan	Spirit Airlines
15 Dec - 09 Jan	Spirit Airlines
30 Dec - 11 Jan	Icelandair
28 Dec - 11 Jan	Icelandair
11 Dec - 07 Jan	Iberia
15 Dec - 10 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.

Book a cheap hotel in London

Cheap car rent in London

Cheapest return flights from Boston to London in December from $409

Return flights