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

Return flights

02 Dec - 09 Dec	Aer Lingus
07 Dec - 15 Jan	SWISS
31 Dec - 07 Jan	SWISS
15 Dec - 22 Dec	SWISS
30 Dec - 06 Jan	SWISS
30 Dec - 30 Jan	SWISS
11 Dec - 14 Dec	SWISS
14 Dec - 21 Dec	SWISS
13 Dec - 23 Dec	SWISS
16 Dec - 15 Jan	SWISS
16 Dec - 06 Jan	SWISS
14 Dec - 28 Dec	SWISS
15 Dec - 29 Dec	SWISS
23 Dec - 09 Jan	SWISS
22 Dec - 09 Jan	TAP
22 Dec - 25 Dec	TAP
24 Dec - 30 Dec	TAP
18 Dec - 31 Dec	Sun Country Airlines
20 Dec - 03 Jan	Sun Country Airlines
20 Dec - 02 Jan	Sun Country Airlines

Also check the deals for one-way flights from San Francisco 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 San Francisco to London in December from 428€

Return flights