AirHint found the following cheapest return flights from Raleigh-durham (RDU) to Keflavik (KEF) in September 2025 (see full year).

Return flights

22 Sep - 01 Oct	Icelandair	direct
23 Sep - 01 Oct	Icelandair	direct
24 Sep - 27 Sep	Frontier Airlines
24 Sep - 28 Sep	Frontier Airlines
23 Sep - 30 Sep	Icelandair
24 Sep - 28 Sep	Icelandair	direct
26 Sep - 01 Oct	Icelandair	direct
18 Sep - 21 Sep	Air Canada
19 Sep - 21 Sep	United
18 Sep - 21 Sep	Icelandair	direct
19 Sep - 21 Sep	Icelandair	direct
24 Sep - 27 Sep	Icelandair	direct

Also check the deals for one-way flights from Raleigh-durham 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 Raleigh-durham to Keflavik in September from $454

Return flights