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

Return flights

02 Sep - 16 Sep	Air Canada
21 Sep - 28 Sep	Air Canada
03 Sep - 10 Sep	Air Canada
22 Sep - 28 Sep	Air Canada
18 Sep - 25 Sep	Air Canada
12 Sep - 23 Sep	Air Canada
03 Sep - 25 Sep	Air Canada
25 Sep - 10 Oct	Air Canada
28 Sep - 12 Oct	Air Canada
12 Sep - 21 Sep	Air Canada
10 Sep - 14 Sep	Air Canada
09 Sep - 16 Sep	Air Canada
27 Sep - 12 Oct	Air Canada
23 Sep - 03 Oct	Air Canada
18 Sep - 14 Oct	Air Canada
28 Sep - 12 Oct	Air Canada	direct
27 Sep - 12 Oct	Lufthansa	direct
03 Sep - 01 Oct	Lufthansa	direct
23 Sep - 03 Oct	Lufthansa	direct
18 Sep - 14 Oct	Lufthansa	direct

Also check the deals for one-way flights from Montreal 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.

Book a cheap hotel in London

Cheap car rent in London

Cheapest return flights from Montreal to London in September from $542

Return flights