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

Return flights

04 Dec - 13 Dec	SWISS
01 Dec - 09 Dec	Aer Lingus
02 Dec - 09 Dec	Aer Lingus
02 Dec - 16 Dec	SWISS
01 Dec - 10 Dec	SWISS
04 Dec - 07 Dec	SWISS
04 Dec - 09 Dec	SWISS
28 Dec - 14 Jan	SWISS
12 Dec - 24 Dec	SWISS
02 Dec - 21 Dec	SWISS
12 Dec - 12 Jan	SWISS
29 Dec - 07 Jan	SWISS
26 Dec - 08 Jan	TAP
12 Dec - 28 Dec	SWISS
16 Dec - 06 Jan	SWISS
24 Dec - 07 Jan	Alaska Airlines
23 Dec - 15 Jan	SWISS
23 Dec - 06 Jan	SWISS
23 Dec - 09 Jan	SWISS
27 Dec - 04 Jan	TAP

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 513€

Return flights