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

Return flights

31 Oct - 09 Nov	Scandinavian Airlines
06 Oct - 15 Oct	Air Canada
22 Oct - 29 Oct	Air Canada
24 Oct - 03 Nov	Air Canada
15 Oct - 22 Oct	Lufthansa
14 Oct - 21 Oct	Air Canada
13 Oct - 08 Nov	Aer Lingus
01 Oct - 05 Oct	Icelandair
20 Oct - 28 Oct	Air Canada
25 Oct - 31 Oct	Scandinavian Airlines
12 Oct - 16 Oct	Icelandair
08 Oct - 15 Oct	Air Canada
07 Oct - 16 Oct	KLM
16 Oct - 08 Nov	Air Canada
12 Oct - 01 Nov	Air Canada
31 Oct - 09 Nov	TAP	direct
29 Oct - 09 Nov	TAP	direct
25 Oct - 02 Nov	Scandinavian Airlines
24 Oct - 02 Nov	Iberia
09 Oct - 01 Nov	SWISS

Also check the deals for one-way flights from Chicago to Lisbon 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 Lisbon in October from $518

Return flights