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

Return flights

09 Dec - 16 Dec	Austrian Airlines
28 Dec - 22 Jan	Lufthansa
30 Dec - 09 Jan	Lufthansa
10 Dec - 31 Jan	Lufthansa
28 Dec - 16 Jan	Lufthansa
09 Dec - 19 Dec	United	direct
09 Dec - 16 Dec	United	direct
11 Dec - 16 Dec	Air Canada
10 Dec - 18 Dec	Air Canada
10 Dec - 17 Dec	Air Canada
29 Dec - 09 Jan	Air Canada
10 Dec - 23 Dec	Air Canada
11 Dec - 15 Dec	Lufthansa
26 Dec - 20 Jan	Lufthansa
10 Dec - 31 Jan	Air France	direct
09 Dec - 15 Dec	United	direct
30 Dec - 10 Jan	Air Canada
30 Dec - 11 Jan	Air Canada
09 Dec - 22 Dec	Air Canada
29 Dec - 11 Jan	Air Canada

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 $575

Return flights