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

Return flights

04 Dec - 08 Dec	Icelandair	direct
30 Dec - 24 Jan	Icelandair	direct
28 Dec - 17 Jan	Icelandair	direct
24 Dec - 29 Dec	Icelandair	direct
21 Dec - 10 Jan	Icelandair	direct
24 Dec - 01 Jan	Icelandair	direct
29 Dec - 01 Jan	Icelandair	direct
20 Dec - 28 Dec	Southwest Airlines
25 Dec - 31 Dec	jetBlue
27 Dec - 01 Jan	Sun Country Airlines
27 Dec - 05 Jan	Sun Country Airlines
26 Dec - 01 Jan	Frontier Airlines
25 Dec - 01 Jan	Frontier Airlines
27 Dec - 30 Dec	Sun Country Airlines
25 Dec - 30 Dec	jetBlue
27 Dec - 01 Jan	Icelandair	direct
26 Dec - 30 Dec	jetBlue

Also check the deals for one-way flights from Denver 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.

Book a cheap hotel in Keflavik

Cheap car rent in Keflavik

Cheapest return flights from Denver to Keflavik in December from 461€

Return flights