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

Return flights

09 Dec - 16 Dec	Delta
04 Dec - 11 Dec	Delta
05 Dec - 10 Dec	Delta
05 Dec - 12 Dec	Delta
07 Dec - 14 Dec	Delta
31 Dec - 13 Jan	Delta
07 Dec - 10 Dec	Frontier Airlines
24 Dec - 08 Jan	Frontier Airlines
13 Dec - 27 Dec	Frontier Airlines
10 Dec - 17 Dec	Delta
16 Dec - 22 Dec	Frontier Airlines
26 Dec - 22 Jan	Delta
10 Dec - 14 Dec	Delta
26 Dec - 09 Jan	Porter Airlines (Canada) Ltd
27 Dec - 08 Jan	Porter Airlines (Canada) Ltd
21 Dec - 03 Jan	Frontier Airlines
26 Dec - 01 Jan	Porter Airlines (Canada) Ltd
22 Dec - 04 Jan	Frontier Airlines
18 Dec - 04 Jan	Frontier Airlines
27 Dec - 01 Jan	Porter Airlines (Canada) Ltd

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 $491

Return flights