Cheapest return flights from Washington to Lisbon in September from $550

Best time to book flights for Washington (IAD) to Lisbon (LIS) flights at AirHint

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

Return flights

17 Sep - 24 Sep Finnair
23 Sep - 30 Sep British Airways
22 Sep - 29 Sep British Airways
21 Sep - 28 Sep Finnair
18 Sep - 25 Sep British Airways
25 Sep - 03 Oct British Airways
02 Sep - 23 Sep Icelandair
16 Sep - 23 Sep Aer Lingus
02 Sep - 09 Sep Air Canada
02 Sep - 16 Sep Aer Lingus
30 Sep - 07 Oct TAP direct
25 Sep - 03 Oct TAP direct
02 Sep - 10 Sep SWISS

Also check the deals for one-way flights from Washington to Lisbon in September.

Skyscanner

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