Cheapest return flights from Seattle to Keflavik in August from $510

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 August 2025 (see full year).

Return flights

13 Aug - 20 Aug Air Canada
19 Aug - 26 Aug Air Canada
02 Aug - 10 Aug Icelandair direct
17 Aug - 24 Aug Icelandair direct
17 Aug - 23 Aug Icelandair direct
19 Aug - 24 Aug Icelandair direct
15 Aug - 25 Aug Icelandair direct
03 Aug - 10 Aug Air France
26 Aug - 02 Sep KLM
04 Aug - 11 Aug Icelandair direct
05 Aug - 12 Aug Icelandair direct
25 Aug - 01 Sep Icelandair direct
27 Aug - 03 Sep Icelandair direct
28 Aug - 04 Sep Icelandair direct
29 Aug - 05 Sep Icelandair direct
26 Aug - 02 Sep Icelandair direct
31 Aug - 07 Sep Icelandair direct
29 Aug - 06 Sep Icelandair direct

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

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.

Book a cheap hotel in Keflavik

Cheap car rent in Keflavik