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

Return flights

25 Sep - 01 Oct	Ryanair
11 Sep - 24 Sep	Ryanair
04 Sep - 10 Sep	Ryanair
11 Sep - 23 Sep	Ryanair
10 Sep - 17 Sep	Ryanair
18 Sep - 24 Sep	Ryanair
04 Sep - 17 Sep	Ryanair
10 Sep - 24 Sep	Ryanair
10 Sep - 23 Sep	Ryanair
11 Sep - 14 Sep	Ryanair
18 Sep - 23 Sep	Ryanair
26 Sep - 02 Oct	Ryanair
05 Sep - 08 Oct	Ryanair
26 Sep - 01 Oct	Ryanair
27 Sep - 04 Oct	Ryanair
29 Sep - 11 Oct	Ryanair
29 Sep - 03 Oct	Ryanair
26 Sep - 11 Oct	Ryanair
26 Sep - 13 Oct	Ryanair
29 Sep - 07 Oct	Ryanair

Also check the deals for one-way flights from Frankfurt 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 Frankfurt to Keflavik in September from 202€

Return flights