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

Return flights

24 Dec - 31 Dec	Ryanair
31 Dec - 06 Jan	Ryanair
30 Dec - 06 Jan	Wizz Air
23 Dec - 30 Dec	Ryanair
26 Dec - 31 Dec	Scandinavian Airlines
24 Dec - 27 Dec	Ryanair
28 Dec - 04 Jan	Ryanair
26 Dec - 30 Dec	Scandinavian Airlines
24 Dec - 28 Dec	Ryanair
21 Dec - 27 Dec	Ryanair
28 Dec - 01 Jan	Wizz Air
21 Dec - 28 Dec	Air Europa
30 Dec - 05 Jan	Wizz Air
29 Dec - 04 Jan	Ryanair
26 Dec - 04 Jan	Ryanair
29 Dec - 05 Jan	Ryanair
28 Dec - 03 Jan	Wizz Air
26 Dec - 03 Jan	Scandinavian Airlines
20 Dec - 23 Dec	Ryanair
25 Dec - 28 Dec	TAP

Also check the deals for one-way flights from Lisbon 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 Lisbon to Keflavik in December from 291€

Return flights