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

Return flights

10 Sep - 07 Oct	Icelandair
10 Sep - 08 Oct	Icelandair
10 Sep - 05 Oct	Icelandair
16 Sep - 23 Sep	Icelandair
22 Sep - 09 Oct	Icelandair
09 Sep - 04 Oct	Icelandair
10 Sep - 04 Oct	Icelandair
25 Sep - 30 Sep	Icelandair
04 Sep - 24 Sep	Icelandair
03 Sep - 17 Sep	Icelandair
04 Sep - 27 Sep	Icelandair
05 Sep - 27 Sep	Icelandair
19 Sep - 11 Oct	Icelandair

Also check the deals for one-way flights from Oakland 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 Oakland to Copenhagen in September from $783

Return flights