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

Return flights

10 Dec - 14 Dec	Icelandair
03 Dec - 10 Dec	Iberia
05 Dec - 12 Dec	Iberia
09 Dec - 16 Dec	SWISS
01 Dec - 08 Dec	Iberia
03 Dec - 10 Dec	TAP	direct
31 Dec - 11 Jan	Icelandair
04 Dec - 11 Dec	Iberia
30 Dec - 13 Jan	Air Canada
11 Dec - 18 Dec	Aer Lingus
07 Dec - 14 Dec	KLM
12 Dec - 23 Dec	Aer Lingus
25 Dec - 17 Jan	Aer Lingus
26 Dec - 17 Jan	Aer Lingus
31 Dec - 07 Jan	Lufthansa
31 Dec - 11 Jan	TAP	direct
28 Dec - 07 Jan	Scandinavian Airlines
26 Dec - 09 Jan	Aer Lingus
22 Dec - 17 Jan	Aer Lingus
30 Dec - 06 Jan	SWISS

Also check the deals for one-way flights from Chicago to Lisbon in December.

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 December from $369

Return flights