AirHint found the following cheapest return flights from Washington (DCA) to Madrid (MAD) in September 2025 (see full year).

Return flights

30 Sep - 07 Oct	Air Canada
30 Sep - 08 Oct	British Airways
02 Sep - 16 Sep	Air Canada
02 Sep - 09 Sep	Air Canada
17 Sep - 24 Sep	British Airways
02 Sep - 18 Sep	Delta
15 Sep - 03 Oct	British Airways
16 Sep - 24 Sep	British Airways
21 Sep - 29 Sep	British Airways
17 Sep - 01 Oct	British Airways
20 Sep - 28 Sep	American Airlines
19 Sep - 28 Sep	American Airlines
04 Sep - 16 Sep	British Airways
13 Sep - 20 Sep	Air Canada
22 Sep - 03 Oct	Iberia
27 Sep - 04 Oct	United

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

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 Madrid in September from $359

Return flights