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

Return flights

05 Sep - 12 Sep	WestJet
03 Sep - 10 Sep	WestJet
19 Sep - 26 Sep	WestJet
09 Sep - 16 Sep	WestJet
28 Sep - 05 Oct	WestJet
07 Sep - 14 Sep	WestJet
26 Sep - 03 Oct	WestJet
11 Sep - 18 Sep	WestJet
27 Sep - 04 Oct	WestJet
01 Sep - 08 Sep	WestJet
23 Sep - 30 Sep	Porter Airlines (Canada) Ltd
16 Sep - 15 Oct	Porter Airlines (Canada) Ltd
02 Sep - 09 Sep	Porter Airlines (Canada) Ltd
06 Sep - 13 Sep	Porter Airlines (Canada) Ltd
24 Sep - 01 Oct	WestJet
29 Sep - 06 Oct	WestJet
25 Sep - 02 Oct	Porter Airlines (Canada) Ltd
14 Sep - 13 Oct	Qatar Airways
30 Sep - 07 Oct	Porter Airlines (Canada) Ltd

Also check the deals for one-way flights from Montreal 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 Montreal to Sydney in September from $1106

Return flights