AirHint found the following cheapest one-way flights from Montreal (YUL) to Chicago (MDW) in September 2025 (see full year).

One-Way flights

24 Sep	Porter Airlines (Canada) Ltd
21 Sep	Porter Airlines (Canada) Ltd
16 Sep	Porter Airlines (Canada) Ltd
30 Sep	Porter Airlines (Canada) Ltd
29 Sep	Porter Airlines (Canada) Ltd
11 Sep	Porter Airlines (Canada) Ltd
14 Sep	Porter Airlines (Canada) Ltd
04 Sep	Porter Airlines (Canada) Ltd
08 Sep	Porter Airlines (Canada) Ltd
09 Sep	Porter Airlines (Canada) Ltd

Also check the deals for return flights from Montreal to Chicago 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 one-way flights from Montreal to Chicago in September from 95€

One-Way flights