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

Return flights

10 Dec - 16 Dec	easyJet
09 Dec - 16 Dec	easyJet
03 Dec - 09 Dec	easyJet
31 Dec - 08 Jan	easyJet
06 Dec - 09 Dec	Ryanair
04 Dec - 09 Dec	Ryanair
31 Dec - 07 Jan	easyJet
08 Dec - 10 Dec	easyJet
07 Dec - 10 Dec	easyJet
12 Dec - 16 Dec	easyJet
11 Dec - 16 Dec	easyJet
02 Dec - 09 Dec	Wizz Air Malta
15 Dec - 01 Jan	Wizz Air Malta
31 Dec - 10 Jan	easyJet
31 Dec - 06 Jan	easyJet
30 Dec - 08 Jan	Iberia
19 Dec - 08 Jan	Wizz Air Malta
31 Dec - 04 Jan	easyJet
19 Dec - 06 Jan	Ryanair
29 Dec - 08 Jan	Ryanair

Also check the deals for one-way flights from Madrid 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 Madrid to Keflavik in December from $213

Return flights