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

Return flights

30 Sep - 22 Oct	Scandinavian Airlines
17 Sep - 29 Oct	Scandinavian Airlines
02 Sep - 09 Sep	United
10 Sep - 17 Sep	United
27 Sep - 02 Oct	Frontier Airlines
04 Sep - 11 Sep	United
08 Sep - 15 Sep	United
16 Sep - 23 Sep	United
06 Sep - 13 Sep	United
13 Sep - 20 Sep	United
22 Sep - 29 Sep	United
28 Sep - 05 Oct	United
19 Sep - 26 Sep	United
25 Sep - 02 Oct	United

Also check the deals for one-way flights from San Francisco to Warsaw 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 Warsaw in September from $543

Return flights