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

Return flights

14 Sep - 18 Sep	Icelandair
14 Sep - 17 Sep	Air Canada
23 Sep - 06 Oct	SWISS
21 Sep - 06 Oct	SWISS
20 Sep - 23 Sep	Air Canada
16 Sep - 23 Sep	SWISS
25 Sep - 07 Oct	Air Canada
14 Sep - 21 Sep	SWISS
21 Sep - 28 Sep	Air Canada
17 Sep - 24 Sep	Air Canada
25 Sep - 06 Oct	Air Canada
18 Sep - 25 Sep	Air Canada
30 Sep - 25 Oct	SWISS
27 Sep - 27 Oct	United
23 Sep - 07 Oct	SWISS
30 Sep - 04 Oct	Hawaiian Airlines
14 Sep - 04 Oct	Air Canada
19 Sep - 22 Sep	Air Canada
26 Sep - 09 Oct	Frontier Airlines
20 Sep - 27 Sep	LOT

Also check the deals for one-way flights from Chicago to Copenhagen 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 Copenhagen in September from $540

Return flights