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

Return flights

03 Dec - 10 Dec	WestJet
05 Dec - 12 Dec	WestJet
01 Dec - 15 Dec	United
01 Dec - 08 Dec	United
02 Dec - 09 Dec	United
01 Dec - 04 Dec	United
04 Dec - 11 Dec	WestJet
07 Dec - 13 Dec	WestJet
06 Dec - 13 Dec	WestJet
08 Dec - 15 Dec	Porter Airlines (Canada) Ltd
25 Dec - 01 Jan	Air Canada
30 Dec - 06 Jan	Air Canada
29 Dec - 05 Jan	Air Canada
31 Dec - 07 Jan	Air Canada
28 Dec - 04 Jan	Finnair
14 Dec - 04 Jan	Porter Airlines (Canada) Ltd
27 Dec - 03 Jan	Finnair
26 Dec - 02 Jan	FrenchBee

Also check the deals for one-way flights from Montreal 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 Montreal to Sydney in December from 1199€

Return flights