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

Return flights

29 Oct - 05 Nov	Air Canada
28 Oct - 04 Nov	Air Canada
18 Oct - 25 Oct	TAP	direct
16 Oct - 23 Oct	Air Canada
16 Oct - 23 Oct	TAP	direct
22 Oct - 29 Oct	TAP	direct
29 Oct - 05 Nov	TAP	direct
31 Oct - 07 Nov	TAP	direct
17 Oct - 24 Oct	TAP	direct
27 Oct - 03 Nov	Air Canada
16 Oct - 24 Oct	TAP	direct
16 Oct - 25 Oct	TAP	direct
24 Oct - 31 Oct	TAP	direct
30 Oct - 06 Nov	Air Canada
20 Oct - 28 Oct	Delta
23 Oct - 30 Oct	Air Canada
26 Oct - 02 Nov	TAP	direct
25 Oct - 02 Nov	TAP	direct
24 Oct - 02 Nov	TAP	direct
31 Oct - 02 Nov	TAP	direct

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 394€

Return flights