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

Return flights

10 Dec - 14 Dec	Frontier Airlines
15 Dec - 10 Jan	Frontier Airlines
13 Dec - 21 Dec	Icelandair
26 Dec - 17 Jan	Scandinavian Airlines
20 Dec - 10 Jan	Frontier Airlines
16 Dec - 30 Dec	Frontier Airlines
20 Dec - 28 Dec	Frontier Airlines
19 Dec - 10 Jan	Frontier Airlines
25 Dec - 17 Jan	Frontier Airlines
30 Dec - 05 Jan	Frontier Airlines
27 Dec - 17 Jan	Frontier Airlines
25 Dec - 31 Dec	Frontier Airlines
27 Dec - 01 Jan	Sun Country Airlines
26 Dec - 01 Jan	Frontier Airlines

Also check the deals for one-way flights from Atlanta 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 Atlanta to Keflavik in December from 583€

Return flights