AirHint found the following cheapest return flights from Washington (IAD) to Lisbon (LIS) in August 2026 (see full year).

Return flights

21 Aug - 27 Aug	Scandinavian Airlines
28 Aug - 04 Sep	Scandinavian Airlines
30 Aug - 10 Sep	Scandinavian Airlines
19 Aug - 23 Aug	Iberia
04 Aug - 11 Aug	Royal Air Maroc
05 Aug - 12 Aug	Royal Air Maroc
01 Aug - 15 Aug	Royal Air Maroc
01 Aug - 08 Aug	Royal Air Maroc
03 Aug - 10 Aug	Royal Air Maroc
07 Aug - 14 Aug	Royal Air Maroc
08 Aug - 15 Aug	Royal Air Maroc
30 Aug - 10 Sep	TAP	direct
02 Aug - 09 Aug	Royal Air Maroc
27 Aug - 03 Sep	TAP	direct
28 Aug - 04 Sep	TAP	direct
29 Aug - 06 Sep	TAP	direct

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.

Book a cheap hotel in Lisbon

Cheap car rent in Lisbon

Cheapest return flights from Washington to Lisbon in August from 555€

Return flights