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 - 27 May	Finnair	direct
05 May - 13 May	Air Canada
05 May - 20 May	Air Canada
02 May - 02 Jun	Air Canada
04 May - 11 May	TAP
10 May - 17 May	TAP
06 May - 25 May	Iberia
01 May - 20 May	Finnair	direct
03 May - 09 May	TAP
17 May - 29 May	Finnair	direct
20 May - 13 Jun	Lufthansa
02 May - 02 Jun	Iberia	direct
29 May - 09 Jun	Aer Lingus
26 May - 01 Jun	Aer Lingus
20 May - 13 Jun	American Airlines	direct
13 May - 24 Jun	TAP
30 May - 06 Jun	Aer Lingus
28 May - 04 Jun	Iberia	direct
29 May - 09 Jun	Finnair	direct

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