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

Return flights

10 Sep - 24 Sep	TAP
09 Sep - 23 Sep	TAP
09 Sep - 30 Sep	TAP
17 Sep - 30 Sep	TAP
25 Sep - 29 Sep	TAP
24 Sep - 29 Sep	TAP
16 Sep - 22 Sep	TAP
09 Sep - 16 Sep	TAP
16 Sep - 23 Sep	TAP
30 Sep - 21 Oct	TAP
17 Sep - 15 Oct	TAP
24 Sep - 16 Oct	TAP
22 Sep - 28 Oct	TAP
03 Sep - 10 Sep	Air Canada
24 Sep - 08 Oct	Delta
03 Sep - 01 Oct	Delta
29 Sep - 09 Oct	Delta
22 Sep - 28 Oct	Delta	direct
30 Sep - 21 Oct	British Airways	direct
24 Sep - 16 Oct	British Airways	direct

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 367€

Return flights