Cheapest return flights from Seattle to Copenhagen in September from $598

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

Return flights

24 Sep - 28 Sep Air Canada
21 Sep - 28 Sep Air Canada
22 Sep - 28 Sep Air Canada
18 Sep - 26 Sep Air Canada
29 Sep - 02 Oct Lufthansa
21 Sep - 28 Sep Scandinavian Airlines direct
20 Sep - 22 Sep Scandinavian Airlines
26 Sep - 11 Oct Lufthansa
24 Sep - 28 Sep Scandinavian Airlines direct
19 Sep - 11 Oct Air Canada

Also check the deals for one-way flights from Seattle to Copenhagen in September.

Skyscanner

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.

Book a cheap hotel in Copenhagen

Cheap car rent in Copenhagen

Feel free to contact us with any feedback or request another flight research.