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

Return flights

01 Dec - 09 Dec	TAP
09 Dec - 15 Dec	SWISS
04 Dec - 08 Dec	SWISS
15 Dec - 22 Dec	SWISS
02 Dec - 09 Dec	Aer Lingus
06 Dec - 14 Dec	TAP
05 Dec - 07 Dec	TAP
29 Dec - 09 Jan	Air Canada
12 Dec - 09 Jan	TAP
10 Dec - 17 Dec	SWISS
04 Dec - 11 Dec	SWISS
11 Dec - 10 Jan	SWISS
30 Dec - 06 Jan	SWISS
30 Dec - 24 Jan	SWISS
07 Dec - 26 Dec	SWISS
16 Dec - 06 Jan	jetBlue
27 Dec - 06 Jan	SWISS
24 Dec - 07 Jan	Alaska Airlines
16 Dec - 05 Jan	Alaska Airlines
24 Dec - 10 Jan	SWISS

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 $420

Return flights