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

Return flights

29 Aug - 07 Sep	Porter Airlines (Canada) Ltd
03 Aug - 11 Aug	Air Canada
06 Aug - 14 Aug	Air Canada
02 Aug - 11 Aug	Air Canada
20 Aug - 25 Aug	Air Canada
18 Aug - 26 Aug	Air Canada
06 Aug - 21 Aug	Air Canada
17 Aug - 25 Aug	Air Canada
13 Aug - 28 Aug	Air Canada
15 Aug - 30 Aug	Air Canada
28 Aug - 04 Sep	Lufthansa
20 Aug - 08 Sep	Lufthansa	direct
22 Aug - 14 Sep	Air Canada
20 Aug - 04 Sep	Air Canada
22 Aug - 06 Sep	Air Canada
20 Aug - 26 Aug	Air Canada
25 Aug - 03 Sep	Lufthansa	direct
31 Aug - 21 Sep	Air Canada
31 Aug - 14 Sep	Air Canada
29 Aug - 21 Sep	Air Canada

Also check the deals for one-way flights from Ottawa 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 Ottawa to London in August from $761

Return flights