AirHint found the following cheapest one-way flights from Ontario (ONT) to London (LHR) in September 2025 (see full year).

One-Way flights

14 Sep	British Airways
08 Sep	British Airways
22 Sep	British Airways
07 Sep	British Airways
26 Sep	jetBlue
01 Sep	British Airways
02 Sep	jetBlue
30 Sep	British Airways
09 Sep	British Airways
03 Sep	British Airways

Also check the deals for return flights from Ontario 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 one-way flights from Ontario to London in September from $395

One-Way flights