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

Return flights

30 Sep - 04 Oct	Ryanair
22 Sep - 27 Sep	Ryanair
29 Sep - 03 Oct	Ryanair
08 Sep - 22 Sep	Ryanair
30 Sep - 08 Oct	Ryanair
18 Sep - 25 Sep	Ryanair
16 Sep - 23 Sep	Ryanair
13 Sep - 16 Sep	Ryanair
23 Sep - 26 Sep	Ryanair
09 Sep - 16 Sep	Ryanair
24 Sep - 04 Oct	Ryanair
26 Sep - 10 Oct	Ryanair
09 Sep - 19 Sep	Ryanair
03 Sep - 17 Sep	Ryanair
19 Sep - 23 Sep	Ryanair
28 Sep - 02 Oct	Ryanair
25 Sep - 02 Oct	Ryanair
26 Sep - 09 Oct	Ryanair

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 169€

Return flights