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

Return flights

30 Sep - 07 Oct	Air Canada
16 Sep - 23 Sep	Air Canada
23 Sep - 30 Sep	Iberia For Level
27 Sep - 18 Oct	Iberia For Level
22 Sep - 29 Sep	Air Canada
17 Sep - 24 Sep	Air Canada
09 Sep - 16 Sep	Air Canada
22 Sep - 29 Sep	TAP	direct
15 Sep - 22 Sep	Air Canada
30 Sep - 07 Oct	TAP	direct
15 Sep - 30 Sep	Brussels Airlines
23 Sep - 30 Sep	TAP	direct
28 Sep - 05 Oct	Air Canada
30 Sep - 23 Oct	TAP	direct
24 Sep - 01 Oct	Air Canada
29 Sep - 06 Oct	SWISS
01 Sep - 15 Sep	SWISS
30 Sep - 09 Oct	United
24 Sep - 01 Oct	TAP	direct
25 Sep - 02 Oct	TAP	direct

Also check the deals for one-way flights from San Francisco to Lisbon 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 Lisbon in September from 406€

Return flights