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

Return flights

17 Sep - 05 Oct	easyJet	direct
17 Sep - 24 Sep	easyJet	direct
30 Sep - 07 Oct	Wizz Air
17 Sep - 23 Sep	easyJet
28 Sep - 14 Oct	easyJet
30 Sep - 04 Oct	Wizz Air
28 Sep - 05 Oct	easyJet	direct
30 Sep - 01 Oct	Wizz Air
21 Sep - 25 Oct	easyJet
14 Sep - 24 Sep	easyJet	direct
07 Sep - 10 Sep	easyJet	direct
28 Sep - 01 Oct	easyJet	direct
28 Sep - 04 Oct	easyJet
24 Sep - 01 Oct	easyJet	direct
10 Sep - 17 Sep	easyJet	direct
14 Sep - 17 Sep	easyJet	direct
21 Sep - 24 Sep	easyJet	direct
07 Sep - 17 Sep	easyJet	direct
22 Sep - 24 Sep	Wizz Air
16 Sep - 23 Sep	Wizz Air

Also check the deals for one-way flights from London 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 London to Keflavik in September from 113€

Return flights