AirHint found the following cheapest return flights from Boston (BOS) to Lisbon (LIS) in August 2025 (see full year).

Return flights

14 Aug - 28 Aug	Lufthansa
21 Aug - 04 Sep	Air Canada
26 Aug - 03 Sep	Air Canada
20 Aug - 28 Aug	Lufthansa
30 Aug - 10 Sep	SWISS
18 Aug - 28 Aug	Lufthansa
26 Aug - 02 Sep	Air Canada
20 Aug - 27 Aug	United
21 Aug - 28 Aug	SWISS
21 Aug - 02 Sep	SWISS
31 Aug - 09 Sep	SWISS
30 Aug - 06 Sep	SWISS
27 Aug - 02 Sep	SWISS
23 Aug - 29 Aug	Aer Lingus
25 Aug - 03 Sep	Lufthansa
11 Aug - 18 Aug	Virgin Atlantic	direct
28 Aug - 03 Sep	Lufthansa
13 Aug - 20 Aug	Virgin Atlantic	direct
19 Aug - 26 Aug	Air Canada
12 Aug - 26 Aug	SWISS

Also check the deals for one-way flights from Boston to Lisbon in August.

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 August from 413€

Return flights