Cheapest return flights from Seattle to Keflavik in December from $614

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 December 2025 (see full year).

Return flights

03 Dec - 11 Dec Hawaiian Airlines
05 Dec - 13 Dec Alaska Airlines
04 Dec - 12 Dec Alaska Airlines
07 Dec - 15 Dec Hawaiian Airlines
02 Dec - 09 Dec Icelandair direct
04 Dec - 12 Dec Icelandair direct
11 Dec - 19 Dec Icelandair direct
01 Dec - 09 Dec Icelandair direct
10 Dec - 18 Dec Icelandair direct
14 Dec - 22 Dec Icelandair direct
31 Dec - 08 Jan Icelandair direct
29 Dec - 06 Jan Icelandair direct
30 Dec - 07 Jan Icelandair direct
27 Dec - 04 Jan Icelandair direct
28 Dec - 05 Jan Icelandair direct
24 Dec - 01 Jan Icelandair direct
26 Dec - 03 Jan Icelandair direct
25 Dec - 02 Jan Icelandair direct

Also check the deals for one-way 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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