Cheapest return flights from Washington to Porto in September from $607

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

Return flights

22 Sep - 07 Oct Air Canada
29 Sep - 07 Oct Air Canada
24 Sep - 18 Oct SWISS
18 Sep - 22 Sep Brussels Airlines
21 Sep - 28 Sep Turkish Airlines
17 Sep - 23 Sep TAP
19 Sep - 26 Sep SWISS
20 Sep - 27 Sep Delta

Also check the deals for one-way flights from Washington to Porto 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 Porto

Cheap car rent in Porto

Feel free to contact us with any feedback or request another flight research.