AirHint found the following cheapest return flights from Ontario (ONT) to Sydney (SYD) in September 2026 (see full year).

Return flights

07 Sep - 20 Sep	Alaska Airlines
23 Sep - 11 Oct	Alaska Airlines
18 Sep - 27 Sep	Alaska Airlines
04 Sep - 18 Sep	China Airlines
05 Sep - 16 Sep	Alaska Airlines
10 Sep - 24 Sep	Alaska Airlines
14 Sep - 20 Sep	China Airlines
16 Sep - 23 Sep	China Airlines
08 Sep - 15 Sep	Qatar Airways
10 Sep - 26 Sep	Qatar Airways
10 Sep - 13 Sep	Qatar Airways

Also check the deals for one-way flights from Ontario 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.

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Cheapest return flights from Ontario to Sydney in September from $1036

Return flights