AirHint found the following cheapest return flights from Chicago (ORD) to Mexico City (MEX) in September 2026 (see full year).

Return flights

21 Sep - 02 Oct	Viva
07 Sep - 17 Sep	Viva
28 Sep - 02 Oct	Viva
21 Sep - 10 Oct	Viva
21 Sep - 23 Sep	Viva
07 Sep - 23 Sep	Viva
08 Sep - 17 Sep	Viva
26 Sep - 02 Oct	Viva
28 Sep - 10 Oct	Viva
21 Sep - 09 Oct	Viva
21 Sep - 07 Oct	Viva
08 Sep - 23 Sep	Viva
27 Sep - 02 Oct	Viva
21 Sep - 08 Oct	Viva
16 Sep - 02 Oct	Viva
07 Sep - 11 Sep	Viva
03 Sep - 07 Sep	Viva	direct
02 Sep - 17 Sep	Viva
02 Sep - 02 Sep	Viva
16 Sep - 17 Sep	Viva

Also check the deals for one-way flights from Chicago to Mexico City 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 Chicago to Mexico City in September from $231

Return flights