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

Return flights

19 Sep - 25 Sep	Brussels Airlines
22 Sep - 29 Sep	FrenchBee
15 Sep - 23 Sep	Air Transat	direct
29 Sep - 06 Oct	FrenchBee
08 Sep - 23 Sep	Air Transat
22 Sep - 06 Oct	FrenchBee
15 Sep - 24 Sep	FrenchBee
21 Sep - 05 Oct	FrenchBee
30 Sep - 06 Oct	Porter Airlines (Canada) Ltd	direct
16 Sep - 23 Sep	Air Transat	direct
28 Sep - 09 Oct	TAP	direct
02 Sep - 09 Sep	SWISS
09 Sep - 16 Sep	SWISS
08 Sep - 17 Sep	SWISS
03 Sep - 25 Sep	SWISS
21 Sep - 06 Oct	FrenchBee
06 Sep - 06 Oct	Delta
21 Sep - 24 Oct	Delta
30 Sep - 22 Oct	Lufthansa
29 Sep - 11 Oct	Delta

Also check the deals for one-way flights from Montreal to Lisbon 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 Lisbon in September from 416€

Return flights