AirHint found the following cheapest return flights from Ontario (ONT) to London (LHR) in August 2025 (see full year).

Return flights

01 Aug - 08 Aug	Delta
29 Aug - 13 Sep	Virgin Atlantic
02 Aug - 09 Aug	Delta
18 Aug - 26 Aug	Iberia
18 Aug - 10 Sep	Iberia
19 Aug - 26 Aug	Iberia
13 Aug - 20 Aug	Iberia
12 Aug - 19 Aug	Iberia
27 Aug - 16 Sep	Iberia
19 Aug - 03 Sep	Iberia
25 Aug - 17 Sep	Iberia
11 Aug - 03 Sep	Iberia
25 Aug - 04 Sep	Iberia
26 Aug - 02 Sep	Iberia
05 Aug - 20 Aug	Iberia
25 Aug - 05 Sep	Iberia
12 Aug - 20 Sep	Iberia
14 Aug - 20 Aug	Iberia
11 Aug - 24 Aug	Iberia
10 Aug - 24 Aug	Iberia

Also check the deals for one-way flights from Ontario to London in August.

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 Ontario to London in August from $614

Return flights