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

Return flights

09 Sep - 16 Sep	TAP
29 Sep - 07 Oct	TAP
16 Sep - 23 Sep	TAP
09 Sep - 29 Sep	TAP
23 Sep - 08 Oct	TAP
08 Sep - 17 Sep	Air Canada
08 Sep - 16 Sep	Air Canada
08 Sep - 01 Oct	Air Canada
09 Sep - 16 Sep	Lufthansa	direct
03 Sep - 10 Sep	Lufthansa	direct
03 Sep - 30 Sep	Lufthansa	direct
03 Sep - 01 Oct	Lufthansa	direct
08 Sep - 01 Oct	Lufthansa	direct
15 Sep - 29 Sep	Air Canada
03 Sep - 17 Sep	Virgin Atlantic
30 Sep - 10 Oct	Delta
09 Sep - 09 Oct	Virgin Atlantic
24 Sep - 24 Oct	Delta
10 Sep - 15 Oct	Delta
30 Sep - 07 Oct	Delta

Also check the deals for one-way flights from San Francisco to London in September.

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 September from 380€

Return flights