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

Return flights

10 Dec - 10 Jan	Hawaiian Airlines
25 Dec - 13 Jan	Turkish Airlines
23 Dec - 12 Jan	Air New Zealand
12 Dec - 11 Jan	Turkish Airlines
10 Dec - 03 Jan	Hawaiian Airlines
11 Dec - 04 Jan	Hawaiian Airlines
27 Dec - 08 Jan	Air New Zealand
06 Dec - 04 Jan	Air New Zealand
18 Dec - 25 Dec	Qantas
12 Dec - 04 Jan	Qantas
19 Dec - 12 Jan	Qantas

Also check the deals for one-way flights from Chicago to Sydney 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 Sydney in December from $1126

Return flights