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

Return flights

11 Aug - 20 Aug	Virgin Atlantic
27 Aug - 02 Sep	Air Canada
12 Aug - 20 Aug	Air Canada
20 Aug - 29 Aug	Air Canada
14 Aug - 20 Aug	Air Canada
15 Aug - 30 Aug	Air Canada
06 Aug - 13 Aug	Air Canada
06 Aug - 14 Aug	Air Canada
04 Aug - 13 Aug	Air Canada
05 Aug - 12 Aug	Air Canada
20 Aug - 25 Aug	Air Canada
31 Aug - 08 Sep	Air Canada
22 Aug - 01 Sep	Air Canada
29 Aug - 05 Sep	Air Canada
30 Aug - 03 Sep	Air Canada
24 Aug - 07 Sep	TAP
29 Aug - 06 Sep	TAP
01 Aug - 01 Sep	British Airways

Also check the deals for one-way flights from Washington 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 Washington to Lisbon in August from $650

Return flights