AirHint found the following cheapest return flights from Toronto (YTZ) to Sofia (SOF) in September 2025 (see full year).

Return flights

27 Sep - 13 Oct	Porter Airlines (Canada) Ltd
28 Sep - 16 Oct	Porter Airlines (Canada) Ltd
15 Sep - 11 Oct	Porter Airlines (Canada) Ltd
20 Sep - 11 Oct	Air Transat
11 Sep - 21 Sep	Porter Airlines (Canada) Ltd
07 Sep - 13 Sep	Air Transat
06 Sep - 12 Sep	Air Transat
07 Sep - 12 Sep	Air Transat
27 Sep - 01 Oct	Air Transat
06 Sep - 13 Sep	Porter Airlines (Canada) Ltd
15 Sep - 30 Sep	SWISS
21 Sep - 06 Oct	SWISS

Also check the deals for one-way flights from Toronto 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 Toronto to Sofia in September from $658

Return flights