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

Return flights

31 Dec - 17 Jan	Frontier Airlines
29 Dec - 17 Jan	Frontier Airlines
22 Dec - 12 Jan	Frontier Airlines
20 Dec - 29 Dec	Frontier Airlines
24 Dec - 11 Jan	Frontier Airlines
18 Dec - 10 Jan	Frontier Airlines
08 Dec - 26 Dec	Frontier Airlines
21 Dec - 16 Jan	Frontier Airlines
14 Dec - 04 Jan	Frontier Airlines
21 Dec - 05 Jan	Frontier Airlines
02 Dec - 27 Dec	Delta
17 Dec - 23 Dec	Delta
12 Dec - 10 Jan	Frontier Airlines
26 Dec - 11 Jan	Delta

Also check the deals for one-way flights from Chicago to Sao Paulo 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.

Book a cheap hotel in Sao Paulo

Cheap car rent in Sao Paulo

Cheapest return flights from Chicago to Sao Paulo in December from 714€

Return flights