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

Return flights

07 May - 21 May	Iberia For Level
19 May - 02 Jun	Iberia For Level
22 May - 05 Jun	Iberia For Level
22 May - 27 May	Iberia For Level
12 May - 19 May	TAP	direct
02 May - 09 May	TAP	direct
19 May - 02 Jun	TAP	direct
22 May - 29 May	TAP	direct
22 May - 05 Jun	TAP	direct

Also check the deals for one-way flights from Boston to Lisbon 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 Lisbon in May from 437€

Return flights