Cheapest return flights from Denver to Keflavik in September from 341€

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

Return flights

29 Sep - 08 Oct Icelandair direct
22 Sep - 26 Sep Frontier Airlines
27 Sep - 04 Oct Frontier Airlines
13 Sep - 15 Sep Frontier Airlines
23 Sep - 01 Oct Frontier Airlines
27 Sep - 04 Oct Icelandair direct
23 Sep - 01 Oct Icelandair direct
20 Sep - 29 Sep Frontier Airlines
21 Sep - 29 Sep Frontier Airlines
22 Sep - 30 Sep Frontier Airlines
21 Sep - 29 Sep Icelandair direct
20 Sep - 28 Sep Frontier Airlines
22 Sep - 26 Sep Icelandair direct
27 Sep - 18 Oct Frontier Airlines
20 Sep - 29 Sep Icelandair direct
27 Sep - 18 Oct Icelandair direct

Also check the deals for one-way flights from Denver to Keflavik in September.

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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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