Cheapest one-way flights from Seattle to Keflavik in December from $372

AirHint found the following cheapest one-way flights from Seattle (SEA) to Keflavik (KEF) in December 2025 (see full year).

One-Way flights

03 Dec WestJet
24 Dec Lufthansa
03 Dec Icelandair direct
24 Dec Icelandair direct
16 Dec Alaska Airlines
27 Dec Icelandair direct
28 Dec Icelandair direct
29 Dec Icelandair direct
30 Dec Icelandair direct
31 Dec Icelandair direct

Also check the deals for return flights from Seattle to Keflavik in December.

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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