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

Return flights

19 Sep - 27 Sep	Frontier Airlines
18 Sep - 27 Sep	Frontier Airlines
14 Sep - 23 Sep	Delta
30 Sep - 07 Oct	Air France
08 Sep - 17 Sep	Air France
07 Sep - 16 Sep	Air France
01 Sep - 10 Sep	KLM
01 Sep - 09 Sep	KLM
22 Sep - 02 Oct	Porter Airlines (Canada) Ltd
09 Sep - 16 Sep	Delta
27 Sep - 04 Oct	Frontier Airlines
21 Sep - 27 Sep	Porter Airlines (Canada) Ltd
17 Sep - 23 Sep	Air France
26 Sep - 07 Oct	Frontier Airlines
25 Sep - 02 Oct	Porter Airlines (Canada) Ltd
13 Sep - 04 Oct	Air France
30 Sep - 06 Oct	Air France
24 Sep - 08 Oct	Delta

Also check the deals for one-way flights from Chicago 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 Chicago to Dublin in September from 492€

Return flights