AirHint found the following cheapest return flights from Chicago (ORD) to Brussels (BRU) in October 2025 (see full year).

Return flights

08 Oct - 15 Oct	Spirit Airlines
09 Oct - 16 Oct	Icelandair
18 Oct - 25 Oct	Icelandair
29 Oct - 05 Nov	United	direct
12 Oct - 19 Oct	Icelandair
08 Oct - 15 Oct	United	direct
15 Oct - 22 Oct	United	direct
21 Oct - 28 Oct	United
14 Oct - 26 Oct	Aer Lingus
09 Oct - 16 Oct	United	direct
24 Oct - 31 Oct	United

Also check the deals for one-way flights from Chicago to Brussels 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.

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Cheapest return flights from Chicago to Brussels in October from 466€

Return flights