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

Return flights

06 Dec - 09 Dec	easyJet
02 Dec - 05 Dec	easyJet
02 Dec - 04 Dec	easyJet
22 Dec - 29 Dec	Fly Play	direct
06 Dec - 10 Dec	easyJet
12 Dec - 15 Dec	Fly Play	direct
01 Dec - 04 Dec	easyJet
08 Dec - 12 Dec	easyJet
15 Dec - 19 Dec	Fly Play	direct
01 Dec - 05 Dec	Fly Play	direct
21 Dec - 11 Jan	easyJet
22 Dec - 02 Jan	Fly Play	direct
23 Dec - 01 Jan	easyJet
29 Dec - 05 Jan	Fly Play	direct
24 Dec - 01 Jan	easyJet
29 Dec - 02 Jan	Fly Play	direct
26 Dec - 02 Jan	Fly Play	direct
31 Dec - 07 Jan	Ryanair
29 Dec - 29 Jan	easyJet
27 Dec - 01 Jan	easyJet

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 $163

Return flights