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

Return flights

16 Sep - 24 Sep	easyJet	direct
06 Sep - 17 Sep	easyJet	direct
16 Sep - 28 Sep	easyJet	direct
23 Sep - 28 Sep	easyJet	direct
13 Sep - 21 Sep	easyJet	direct
20 Sep - 28 Sep	easyJet	direct
13 Sep - 20 Sep	easyJet
02 Sep - 09 Sep	easyJet
22 Sep - 24 Sep	easyJet
22 Sep - 28 Sep	easyJet
28 Sep - 12 Oct	Norwegian

Also check the deals for one-way flights from Basel 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 Basel to Keflavik in September from $109

Return flights