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

Return flights

09 Dec - 13 Dec	easyJet
11 Dec - 13 Dec	easyJet
09 Dec - 11 Dec	easyJet
06 Dec - 10 Dec	easyJet
08 Dec - 12 Dec	easyJet
08 Dec - 11 Dec	easyJet
01 Dec - 13 Dec	easyJet
10 Dec - 16 Dec	easyJet
06 Dec - 13 Dec	easyJet
08 Dec - 14 Dec	easyJet
31 Dec - 15 Jan	easyJet
22 Dec - 06 Jan	easyJet
31 Dec - 06 Jan	easyJet
23 Dec - 05 Jan	easyJet
22 Dec - 01 Jan	easyJet
30 Dec - 03 Jan	Ryanair
23 Dec - 01 Jan	easyJet
22 Dec - 03 Jan	easyJet
29 Dec - 06 Jan	easyJet
31 Dec - 04 Jan	Ryanair

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 160€

Return flights