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

Return flights

04 Sep - 07 Sep	Hawaiian Airlines
03 Sep - 10 Sep	Hawaiian Airlines
09 Sep - 16 Sep	Cathay Pacific
17 Sep - 30 Sep	Hawaiian Airlines
02 Sep - 25 Sep	Hawaiian Airlines
01 Sep - 06 Sep	ANA
10 Sep - 21 Sep	Hawaiian Airlines
09 Sep - 21 Sep	Hawaiian Airlines
17 Sep - 01 Oct	Hawaiian Airlines
20 Sep - 29 Sep	Hawaiian Airlines
14 Sep - 28 Sep	Air Canada

Also check the deals for one-way flights from Chicago to Sydney in September.

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 Sydney

Cheap car rent in Sydney

Cheapest return flights from Chicago to Sydney in September from 896€

Return flights