AirHint found the following cheapest one-way flights from Chicago (MDW) to Madrid (MAD) in October 2025 (see full year).

One-Way flights

07 Oct	Frontier Airlines
27 Oct	Frontier Airlines
06 Oct	Frontier Airlines
16 Oct	Frontier Airlines
11 Oct	Frontier Airlines
03 Oct	Frontier Airlines
24 Oct	Frontier Airlines
31 Oct	Frontier Airlines
04 Oct	Frontier Airlines
10 Oct	Frontier Airlines

Also check the deals for return flights from Chicago to Madrid in October.

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 Madrid

Cheap car rent in Madrid

Cheapest one-way flights from Chicago to Madrid in October from $258

One-Way flights