AirHint found the following cheapest return flights from Montreal (YUL) to Sofia (SOF) in September 2026 (see full year).

Return flights

27 Sep - 04 Oct	British Airways
13 Sep - 20 Sep	British Airways
20 Sep - 27 Sep	British Airways
30 Sep - 07 Oct	Finnair
23 Sep - 30 Sep	Finnair
16 Sep - 23 Sep	Finnair
15 Sep - 22 Sep	Air Transat
08 Sep - 15 Sep	Air Transat
29 Sep - 06 Oct	Air Canada
02 Sep - 09 Sep	Air Canada
07 Sep - 14 Sep	Air Canada
14 Sep - 21 Sep	Air Canada
21 Sep - 28 Sep	Air Canada
28 Sep - 05 Oct	Air Canada
24 Sep - 01 Oct	Air Canada
25 Sep - 02 Oct	Turkish Airlines
26 Sep - 03 Oct	Air Canada

Also check the deals for one-way flights from Montreal to Sofia 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 Sofia in September from $759

Return flights