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

Return flights

30 Dec - 13 Jan	Lufthansa
30 Dec - 13 Jan	Icelandair	direct
30 Dec - 08 Jan	Icelandair
30 Dec - 06 Jan	Icelandair	direct
31 Dec - 07 Jan	Icelandair
30 Dec - 08 Jan	Icelandair	direct
31 Dec - 07 Jan	Icelandair	direct
29 Dec - 07 Jan	Lufthansa
28 Dec - 31 Dec	Icelandair	direct
27 Dec - 31 Dec	Icelandair	direct
27 Dec - 29 Dec	Icelandair	direct
31 Dec - 05 Jan	SWISS
29 Dec - 07 Jan	Icelandair	direct
27 Dec - 30 Dec	Icelandair	direct
28 Dec - 30 Dec	Icelandair	direct

Also check the deals for one-way flights from Newark 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 Newark to Keflavik in December from 655€

Return flights