AirHint found the following cheapest return flights from Toronto (YYZ) to London (LTN) in September 2025 (see full year).

Return flights

30 Sep - 08 Oct	Air Transat
11 Sep - 16 Sep	TAP
01 Sep - 09 Sep	TAP
01 Sep - 16 Sep	TAP
10 Sep - 16 Sep	TAP
22 Sep - 25 Sep	Air Transat
03 Sep - 14 Sep	TAP
01 Sep - 05 Sep	TAP
01 Sep - 10 Sep	TAP
30 Sep - 07 Oct	Icelandair
30 Sep - 05 Oct	Air Transat
01 Sep - 12 Sep	TAP
03 Sep - 24 Sep	TAP
28 Sep - 05 Oct	WestJet
30 Sep - 20 Oct	Air Transat
27 Sep - 09 Oct	Icelandair
22 Sep - 01 Oct	Air Transat
26 Sep - 05 Oct	Air Transat
22 Sep - 09 Oct	Air Transat
29 Sep - 01 Oct	Porter Airlines (Canada) Ltd

Also check the deals for one-way flights from Toronto to London 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 London in September from 421€

Return flights