AirHint found the following cheapest return flights from Mexico City (MEX) to Chicago (ORD) in September 2025 (see full year).

Return flights

23 Sep - 30 Sep	Viva
28 Sep - 07 Oct	Viva
30 Sep - 07 Oct	Viva
28 Sep - 30 Sep	Viva
28 Sep - 09 Oct	Viva
30 Sep - 09 Oct	Viva
27 Sep - 07 Oct	Viva
21 Sep - 07 Oct	Viva
27 Sep - 30 Sep	Viva
30 Sep - 06 Oct	Viva
26 Sep - 05 Oct	Volaris	direct
28 Sep - 11 Oct	Viva
28 Sep - 12 Oct	Viva
21 Sep - 30 Sep	Viva
25 Sep - 30 Sep	Viva
26 Sep - 30 Sep	Viva
27 Sep - 29 Sep	Viva
24 Sep - 30 Sep	Viva
22 Sep - 29 Sep	Viva
09 Sep - 30 Sep	Viva

Also check the deals for one-way flights from Mexico City 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 return flights from Mexico City to Chicago in September from $212

Return flights