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

Return flights

01 Dec - 05 Dec	easyJet
19 Dec - 12 Jan	easyJet
22 Dec - 12 Jan	easyJet
19 Dec - 11 Jan	easyJet
30 Dec - 06 Jan	easyJet
28 Dec - 31 Dec	easyJet
22 Dec - 16 Jan	easyJet
01 Dec - 01 Dec	Wizz Air
29 Dec - 07 Jan	easyJet
20 Dec - 11 Jan	easyJet
22 Dec - 16 Jan	Fly Play	direct
30 Dec - 03 Jan	easyJet
21 Dec - 11 Jan	easyJet
18 Dec - 25 Dec	easyJet
18 Dec - 28 Dec	easyJet
19 Dec - 29 Dec	easyJet
01 Dec - 05 Dec	Fly Play	direct
26 Dec - 29 Dec	Fly Play	direct
19 Dec - 26 Dec	easyJet
19 Dec - 29 Dec	Fly Play	direct

Also check the deals for one-way flights from Keflavik to Madrid 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 Keflavik to Madrid in December from 158€

Return flights