AirHint found the following cheapest return flights from Lisbon (LIS) to Keflavik (KEF) in September 2026 (see full year).

Return flights

29 Sep - 06 Oct	easyJet
30 Sep - 07 Oct	easyJet
29 Sep - 08 Oct	easyJet
26 Sep - 03 Oct	Vueling Airlines
23 Sep - 03 Oct	Vueling Airlines
23 Sep - 30 Sep	easyJet
30 Sep - 03 Oct	Vueling Airlines
16 Sep - 03 Oct	Vueling Airlines
15 Sep - 22 Sep	Vueling Airlines
24 Sep - 01 Oct	easyJet
14 Sep - 21 Sep	Vueling Airlines
16 Sep - 23 Sep	Vueling Airlines
26 Sep - 30 Sep	Vueling Airlines
28 Sep - 05 Oct	easyJet
22 Sep - 29 Sep	Vueling Airlines
19 Sep - 03 Oct	Vueling Airlines
24 Sep - 29 Sep	easyJet
16 Sep - 30 Sep	Vueling Airlines
21 Sep - 28 Sep	easyJet
12 Sep - 16 Sep	Vueling Airlines

Also check the deals for one-way flights from Lisbon 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 Lisbon to Keflavik in September from $235

Return flights