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

Return flights

10 Sep - 24 Sep	easyJet
24 Sep - 02 Oct	Ryanair
11 Sep - 17 Sep	Ryanair
26 Sep - 05 Oct	Pegasus Airlines
10 Sep - 17 Sep	Wizz Air
17 Sep - 24 Sep	Wizz Air
16 Sep - 24 Sep	Wizz Air
22 Sep - 02 Oct	Wizz Air
01 Sep - 06 Sep	Wizz Air
02 Sep - 07 Sep	Ryanair
18 Sep - 28 Sep	Wizz Air UK
27 Sep - 03 Oct	easyJet
08 Sep - 13 Sep	Pegasus Airlines
16 Sep - 20 Sep	Wizz Air
27 Sep - 05 Oct	Ryanair
26 Sep - 06 Oct	easyJet
23 Sep - 07 Oct	Wizz Air
29 Sep - 05 Oct	Air Serbia
26 Sep - 09 Oct	easyJet

Also check the deals for one-way flights from Athens 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 Athens to Keflavik in September from 229€

Return flights