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

Return flights

05 Dec - 13 Dec	British Airways
15 Dec - 22 Dec	jetBlue
23 Dec - 30 Dec	Icelandair
23 Dec - 31 Dec	Icelandair
24 Dec - 31 Dec	Icelandair
29 Dec - 06 Jan	Icelandair
27 Dec - 04 Jan	Icelandair
28 Dec - 05 Jan	Icelandair
25 Dec - 02 Jan	Scandinavian Airlines
24 Dec - 01 Jan	Icelandair
25 Dec - 01 Jan	Icelandair
26 Dec - 03 Jan	Icelandair
26 Dec - 02 Jan	Icelandair
27 Dec - 30 Dec	British Airways

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 $721

Return flights