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

Return flights

23 Sep - 30 Sep	Iberia
30 Sep - 07 Oct	Iberia
24 Sep - 01 Oct	Iberia
14 Sep - 25 Sep	Delta
02 Sep - 12 Sep	Delta
10 Sep - 19 Sep	Delta
20 Sep - 30 Sep	Iberia
19 Sep - 03 Oct	Iberia
15 Sep - 22 Sep	British Airways
06 Sep - 26 Sep	Air Canada
01 Sep - 10 Sep	Air Canada
01 Sep - 12 Sep	Air Canada
11 Sep - 18 Sep	British Airways
27 Sep - 04 Oct	Iberia
04 Sep - 22 Oct	Delta

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 312€

Return flights