Cheapest return flights from Seattle to Keflavik in September from 361€

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

Return flights

16 Sep - 23 Sep Air Canada
26 Sep - 09 Oct Icelandair direct
16 Sep - 24 Sep Icelandair direct
30 Sep - 08 Oct Icelandair direct
14 Sep - 23 Sep Air Canada
07 Sep - 16 Sep Air France
13 Sep - 18 Sep Air France
01 Sep - 09 Sep Delta
09 Sep - 17 Sep Air France
08 Sep - 16 Sep Delta
16 Sep - 23 Sep Icelandair direct
14 Sep - 23 Sep Icelandair direct
27 Sep - 04 Oct Air Canada
26 Sep - 03 Oct Air Canada
30 Sep - 11 Oct Air France
27 Sep - 10 Oct Icelandair direct
24 Sep - 03 Oct Air Canada
26 Sep - 03 Oct Icelandair direct
30 Sep - 11 Oct Icelandair direct
24 Sep - 03 Oct Icelandair direct

Also check the deals for one-way flights from Seattle to Keflavik in September.

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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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