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

Return flights

01 Sep - 07 Sep	TAP
01 Sep - 08 Sep	TAP
25 Sep - 30 Sep	TAP
25 Sep - 29 Sep	TAP
02 Sep - 11 Sep	TAP
06 Sep - 17 Sep	TAP
22 Sep - 30 Sep	TAP
29 Sep - 13 Oct	TAP
07 Sep - 15 Sep	TAP
16 Sep - 30 Sep	TAP
02 Sep - 09 Sep	TAP
25 Sep - 02 Oct	TAP
24 Sep - 07 Oct	TAP
28 Sep - 05 Oct	TAP
22 Sep - 01 Oct	Scandinavian Airlines
25 Sep - 01 Oct	Scandinavian Airlines
27 Sep - 04 Oct	Scandinavian Airlines
09 Sep - 27 Oct	SWISS
09 Sep - 27 Oct	Aer Lingus	direct
29 Sep - 13 Oct	Aer Lingus	direct

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.

Book a cheap hotel in Dublin

Cheap car rent in Dublin

Cheapest return flights from Washington to Dublin in September from $428

Return flights