Cheapest return flights from Seattle to Keflavik in September from 570€

Best time to book flights for Seattle (SEA) to Keflavik (KEF) flights at AirHint

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

Return flights

16 Sep - 01 Oct jetBlue
03 Sep - 11 Sep jetBlue
30 Sep - 08 Oct Alaska Airlines
27 Sep - 07 Oct jetBlue
23 Sep - 02 Oct jetBlue
04 Sep - 11 Sep jetBlue
23 Sep - 29 Sep jetBlue
13 Sep - 22 Sep jetBlue
13 Sep - 23 Sep jetBlue
23 Sep - 03 Oct Air Canada
17 Sep - 02 Oct jetBlue
22 Sep - 02 Oct jetBlue
24 Sep - 01 Oct Air Canada
20 Sep - 01 Oct jetBlue
06 Sep - 17 Sep jetBlue
06 Sep - 13 Sep jetBlue
04 Sep - 12 Sep jetBlue
05 Sep - 11 Sep jetBlue
12 Sep - 18 Sep jetBlue
23 Sep - 04 Oct jetBlue

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

Skyscanner

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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