AirHint found the following cheapest return flights from Washington (DCA) to Keflavik (KEF) in December 2025 (see full year).

Return flights

03 Dec - 07 Dec	Scandinavian Airlines
11 Dec - 15 Dec	jetBlue
14 Dec - 18 Dec	Icelandair
11 Dec - 14 Dec	Icelandair
17 Dec - 10 Jan	Icelandair
24 Dec - 17 Jan	Frontier Airlines
06 Dec - 27 Dec	Icelandair
18 Dec - 10 Jan	Icelandair
18 Dec - 21 Dec	Icelandair
27 Dec - 17 Jan	Icelandair
27 Dec - 06 Jan	Icelandair
23 Dec - 29 Dec	Icelandair
26 Dec - 17 Jan	Icelandair
31 Dec - 04 Jan	jetBlue
29 Dec - 04 Jan	jetBlue
26 Dec - 31 Dec	Icelandair
19 Dec - 23 Dec	Icelandair
12 Dec - 03 Jan	Icelandair
18 Dec - 02 Jan	Icelandair

Also check the deals for one-way flights from Washington to Keflavik in December.

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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Cheapest return flights from Washington to Keflavik in December from 550€

Return flights