Cheapest return flights from Ontario to London in May from $786

AirHint found the following cheapest return flights from Ontario (ONT) to London (STN) in May 2026 (see full year).

Return flights

06 May - 21 May Alaska Airlines
13 May - 14 Jun Frontier Airlines
05 May - 01 Jun Frontier Airlines
06 May - 10 Jun Alaska Airlines
01 May - 31 May Alaska Airlines
15 May - 14 Jun Alaska Airlines
16 May - 14 Jun Alaska Airlines
06 May - 03 Jun Alaska Airlines
20 May - 10 Jun Alaska Airlines
14 May - 14 Jun Alaska Airlines
02 May - 17 May Frontier Airlines

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

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