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

Return flights

10 Sep - 02 Oct	easyJet
25 Sep - 29 Sep	Wizz Air Malta
20 Sep - 01 Oct	easyJet
29 Sep - 30 Sep	Fly Play
11 Sep - 12 Sep	Fly Play
28 Sep - 29 Sep	Wizz Air
19 Sep - 30 Sep	Fly Play
26 Sep - 29 Sep	Fly Play
10 Sep - 02 Oct	Icelandair	direct
11 Sep - 12 Sep	Icelandair	direct
25 Sep - 29 Sep	Icelandair	direct
20 Sep - 01 Oct	Icelandair	direct
28 Sep - 29 Sep	Icelandair	direct
26 Sep - 29 Sep	Icelandair	direct

Also check the deals for one-way flights from Keflavik to Brussels 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 Keflavik to Brussels in September from $313

Return flights