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

Return flights

02 Dec - 09 Dec	easyJet
03 Dec - 09 Dec	easyJet
09 Dec - 11 Dec	easyJet
08 Dec - 11 Dec	easyJet
12 Dec - 15 Dec	Transavia France
13 Dec - 16 Dec	easyJet
10 Dec - 13 Dec	easyJet
11 Dec - 15 Dec	easyJet
08 Dec - 12 Dec	Scandinavian Airlines
10 Dec - 17 Dec	easyJet
21 Dec - 04 Jan	Ryanair
30 Dec - 05 Jan	Wizz Air
26 Dec - 01 Jan	Ryanair
27 Dec - 04 Jan	TAP
29 Dec - 02 Jan	Ryanair
28 Dec - 02 Jan	Ryanair
27 Dec - 02 Jan	Ryanair
28 Dec - 01 Jan	Icelandair	direct
28 Dec - 04 Jan	Icelandair	direct

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 188€

Return flights