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

Return flights

14 Sep - 23 Sep	Air Canada
08 Sep - 11 Sep	Air Canada
24 Sep - 01 Oct	Air Canada
12 Sep - 23 Oct	Virgin Atlantic
29 Sep - 25 Oct	Scandinavian Airlines
16 Sep - 30 Sep	Icelandair
21 Sep - 11 Oct	Scandinavian Airlines
20 Sep - 11 Oct	Scandinavian Airlines
26 Sep - 07 Oct	Scandinavian Airlines
14 Sep - 21 Sep	Icelandair

Also check the deals for one-way flights from Washington 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 Washington to Copenhagen in September from $536

Return flights