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

Return flights

27 Sep - 14 Oct	Air Canada
28 Sep - 07 Oct	Air Canada
28 Sep - 23 Oct	Iberia
30 Sep - 07 Oct	Air Canada
23 Sep - 07 Oct	Air Canada
22 Sep - 01 Oct	Air Canada
23 Sep - 01 Oct	Air Canada
30 Sep - 08 Oct	Air Canada
30 Sep - 16 Oct	Air Canada
28 Sep - 09 Oct	Lufthansa
21 Sep - 30 Sep	Virgin Australia
16 Sep - 23 Sep	Delta
20 Sep - 30 Sep	Air Canada
21 Sep - 24 Sep	SWISS
23 Sep - 29 Sep	British Airways
24 Sep - 29 Sep	British Airways
23 Sep - 28 Sep	SWISS
17 Sep - 22 Sep	Aer Lingus
24 Sep - 28 Sep	SWISS
18 Sep - 23 Sep	Aer Lingus

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 $410

Return flights