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

Return flights

25 Oct - 02 Nov	Icelandair
27 Oct - 04 Nov	KLM
26 Oct - 05 Nov	KLM
08 Oct - 19 Oct	Icelandair
11 Oct - 19 Oct	Icelandair
21 Oct - 08 Nov	Finnair
22 Oct - 09 Nov	Air France
22 Oct - 15 Nov	Air France
31 Oct - 05 Nov	KLM
29 Oct - 09 Nov	KLM
22 Oct - 09 Nov	TAP	direct
23 Oct - 02 Nov	KLM
08 Oct - 22 Oct	Lufthansa
05 Oct - 08 Oct	Frontier Airlines
22 Oct - 30 Oct	United
17 Oct - 19 Oct	Air France
09 Oct - 31 Oct	SWISS
07 Oct - 29 Oct	Lufthansa
19 Oct - 23 Oct	Spirit Airlines
16 Oct - 19 Oct	KLM

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 352€

Return flights