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

Return flights

04 Sep - 11 Sep	Fly Play	direct
14 Sep - 21 Sep	Fly Play	direct
04 Sep - 07 Sep	Fly Play	direct
03 Sep - 07 Sep	Wizz Air
28 Sep - 09 Oct	Fly Play	direct
25 Sep - 02 Oct	Fly Play	direct
28 Sep - 05 Oct	Fly Play	direct
25 Sep - 05 Oct	Fly Play	direct
23 Sep - 30 Sep	Norwegian Air Sweden AOC
04 Sep - 09 Sep	Fly Play
01 Sep - 04 Sep	Icelandair
23 Sep - 05 Oct	Norwegian Air Sweden AOC
26 Sep - 30 Sep	airBaltic
25 Sep - 03 Oct	LOT
26 Sep - 05 Oct	Wizz Air
06 Sep - 13 Sep	Lufthansa
06 Sep - 11 Sep	Lufthansa
25 Sep - 04 Oct	Lufthansa
27 Sep - 05 Oct	Scandinavian Airlines
27 Sep - 04 Oct	Lufthansa

Also check the deals for one-way flights from Billund 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 Billund to Keflavik in September from $189

Return flights