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

Return flights

29 Sep - 08 Oct	TAP
12 Sep - 19 Sep	ITA Airways
30 Sep - 25 Oct	TAP
07 Sep - 16 Sep	TAP
07 Sep - 17 Sep	TAP
30 Sep - 07 Oct	TAP
21 Sep - 26 Sep	ITA Airways
27 Sep - 01 Oct	TAP
14 Sep - 04 Oct	TAP
06 Sep - 11 Sep	TAP
22 Sep - 29 Sep	SWISS
15 Sep - 22 Sep	Air Canada
24 Sep - 18 Oct	Scandinavian Airlines
15 Sep - 15 Oct	United
24 Sep - 05 Oct	Air Canada
16 Sep - 21 Oct	United
13 Sep - 23 Sep	Iberia
18 Sep - 02 Oct	Brussels Airlines
23 Sep - 28 Sep	Air Canada
19 Sep - 23 Sep	Delta

Also check the deals for one-way flights from Washington to Barcelona 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 Barcelona in September from $404

Return flights