AirHint found the following cheapest return flights from Detroit (DTW) to Keflavik (KEF) in September 2025 (see full year).

Return flights

30 Sep - 07 Oct	Icelandair	direct
29 Sep - 07 Oct	Icelandair	direct
29 Sep - 06 Oct	Icelandair	direct
22 Sep - 29 Sep	Icelandair	direct
08 Sep - 15 Sep	Icelandair	direct
11 Sep - 18 Sep	Icelandair	direct
23 Sep - 30 Sep	Icelandair	direct
30 Sep - 14 Oct	Air France
29 Sep - 14 Oct	Air France
04 Sep - 25 Sep	Air France
02 Sep - 09 Sep	United
05 Sep - 12 Sep	United
30 Sep - 14 Oct	Icelandair	direct
29 Sep - 14 Oct	Icelandair	direct
02 Sep - 09 Sep	Icelandair	direct
04 Sep - 25 Sep	Icelandair	direct
17 Sep - 24 Sep	United

Also check the deals for one-way flights from Detroit to Keflavik 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 Detroit to Keflavik in September from 279€

Return flights