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

Return flights

11 Aug - 25 Aug	Icelandair
14 Aug - 21 Aug	Icelandair
15 Aug - 01 Sep	Icelandair
15 Aug - 22 Aug	Icelandair
22 Aug - 12 Sep	Icelandair
16 Aug - 17 Sep	Icelandair
20 Aug - 27 Aug	Icelandair
08 Aug - 16 Aug	Icelandair
22 Aug - 27 Aug	Icelandair
21 Aug - 31 Aug	Icelandair
17 Aug - 24 Aug	Icelandair
19 Aug - 26 Aug	Icelandair
27 Aug - 03 Sep	Icelandair
25 Aug - 03 Sep	Icelandair
13 Aug - 20 Aug	Icelandair
25 Aug - 10 Sep	Icelandair
25 Aug - 10 Sep	Scandinavian Airlines	direct
29 Aug - 05 Sep	Icelandair
31 Aug - 07 Sep	Icelandair
25 Aug - 01 Sep	Icelandair

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

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 Seattle to Copenhagen in August from $422

Return flights