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

Return flights

10 Sep - 24 Sep	jetBlue
22 Sep - 23 Oct	United
14 Sep - 21 Sep	jetBlue
30 Sep - 13 Oct	Delta
30 Sep - 12 Oct	Delta
29 Sep - 12 Oct	Delta
29 Sep - 13 Oct	Delta
20 Sep - 27 Sep	United
19 Sep - 21 Sep	Delta
15 Sep - 18 Sep	Air Canada
20 Sep - 26 Sep	Air Canada
21 Sep - 27 Sep	United
19 Sep - 22 Sep	jetBlue
24 Sep - 18 Oct	United
26 Sep - 18 Oct	United
26 Sep - 01 Oct	United
24 Sep - 28 Sep	United
10 Sep - 17 Sep	jetBlue
25 Sep - 18 Oct	Scandinavian Airlines
26 Sep - 05 Oct	jetBlue

Also check the deals for one-way flights from Washington to Dublin 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 Dublin in September from 455€

Return flights