AirHint found the following cheapest return flights from Madrid (MAD) to Keflavik (KEF) in May 2026 (see full year).

Return flights

22 May - 29 May	Fly Play	direct
08 May - 15 May	Fly Play	direct
01 May - 08 May	Fly Play	direct
15 May - 22 May	Fly Play	direct
15 May - 20 May	Fly Play	direct
22 May - 01 Jun	Fly Play	direct
01 May - 04 May	Fly Play	direct
15 May - 25 May	Fly Play	direct
08 May - 18 May	Fly Play	direct
30 May - 06 Jun	Wizz Air UK
10 May - 16 May	Iberia
09 May - 17 May	Iberia Express
30 May - 10 Jun	Wizz Air UK

Also check the deals for one-way flights from Madrid to Keflavik in May.

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 May from 155€

Return flights