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

Return flights

28 Sep - 23 Oct	Iberia For Level	direct
28 Sep - 19 Oct	Iberia For Level	direct
23 Sep - 02 Oct	Iberia For Level	direct
21 Sep - 02 Oct	Iberia
21 Sep - 18 Oct	Iberia
23 Sep - 30 Sep	Iberia For Level	direct
21 Sep - 02 Oct	Iberia For Level	direct
22 Sep - 30 Sep	Air Canada
21 Sep - 30 Sep	United	direct
30 Sep - 08 Oct	United
30 Sep - 14 Oct	United
21 Sep - 01 Oct	United	direct
08 Sep - 15 Sep	TAP
10 Sep - 15 Sep	TAP
02 Sep - 16 Sep	TAP
27 Sep - 23 Oct	Iberia	direct
23 Sep - 28 Sep	Iberia For Level	direct
09 Sep - 16 Sep	Iberia For Level	direct
16 Sep - 23 Sep	Iberia For Level	direct
03 Sep - 15 Sep	TAP

Also check the deals for one-way flights from San Francisco to Barcelona 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 Barcelona in September from 346€

Return flights