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

Return flights

19 May - 02 Jun	Air Canada
13 May - 20 May	Iberia	direct
12 May - 18 May	Iberia
18 May - 13 Jun	Air Canada
12 May - 18 May	American Airlines	direct
03 May - 10 May	Iberia	direct
15 May - 30 May	British Airways	direct
26 May - 02 Jun	Aer Lingus
19 May - 02 Jun	British Airways	direct
27 May - 03 Jun	Aer Lingus
28 May - 07 Jun	Aer Lingus
23 May - 30 May	Iberia	direct
26 May - 02 Jun	Delta	direct
28 May - 07 Jun	Delta	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 $373

Return flights