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

Return flights

06 May - 13 May	Iberia	direct
04 May - 29 May	Finnair	direct
06 May - 12 May	Finnair
06 May - 12 May	Air France	direct
12 May - 19 May	TAP
01 May - 20 May	Finnair	direct
09 May - 18 May	TAP
13 May - 26 May	Air France	direct
12 May - 19 May	Iberia	direct
01 May - 04 May	Iberia	direct
29 May - 09 Jun	Aer Lingus
26 May - 01 Jun	Aer Lingus
26 May - 02 Jun	Air Canada
27 May - 09 Jun	Aer Lingus
22 May - 05 Jun	Aer Lingus
27 May - 08 Jun	TAP
13 May - 24 Jun	TAP
25 May - 07 Jun	TAP
28 May - 07 Jun	Aer Lingus
27 May - 07 Jun	TAP

Also check the deals for one-way flights from Boston to Madrid 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 Boston to Madrid in May from $350

Return flights