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

Return flights

27 Sep - 08 Oct	Vueling Airlines
23 Sep - 28 Sep	Vueling Airlines
27 Sep - 05 Oct	Vueling Airlines
26 Sep - 05 Oct	Vueling Airlines
24 Sep - 28 Sep	Vueling Airlines
20 Sep - 27 Sep	Vueling Airlines
26 Sep - 30 Sep	Vueling Airlines
19 Sep - 28 Sep	Vueling Airlines
28 Sep - 02 Oct	Vueling Airlines

Also check the deals for one-way flights from Bilbao 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 Bilbao to Keflavik in September from 248€

Return flights