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

Return flights

22 Sep - 07 Oct	SWISS
30 Sep - 14 Oct	SWISS
23 Sep - 30 Sep	SWISS
28 Sep - 12 Oct	Lufthansa
28 Sep - 05 Oct	SWISS
23 Sep - 11 Oct	SWISS
23 Sep - 18 Oct	Austrian Airlines
24 Sep - 01 Oct	British Airways
30 Sep - 09 Oct	SWISS
21 Sep - 30 Sep	Air Canada
26 Sep - 18 Oct	SWISS
23 Sep - 26 Oct	Scandinavian Airlines
26 Sep - 30 Sep	Austrian Airlines
17 Sep - 25 Sep	British Airways
20 Sep - 27 Sep	Frontier Airlines
18 Sep - 29 Sep	Frontier Airlines
17 Sep - 22 Sep	Air Canada
18 Sep - 27 Sep	Frontier Airlines
18 Sep - 21 Sep	Frontier Airlines
26 Sep - 30 Sep	LOT	direct

Also check the deals for one-way flights from Chicago 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 Chicago to Warsaw in September from $513

Return flights