AirHint found the following cheapest return flights from Ontario (ONT) to Seoul (ICN) in September 2025 (see full year).

Return flights

30 Sep - 14 Oct	China Airlines
29 Sep - 12 Oct	China Airlines
29 Sep - 11 Oct	China Airlines
30 Sep - 09 Oct	China Airlines
30 Sep - 12 Oct	China Airlines
30 Sep - 13 Oct	China Airlines
30 Sep - 10 Oct	China Airlines
30 Sep - 21 Oct	China Airlines
30 Sep - 22 Oct	China Airlines
24 Sep - 08 Oct	China Airlines
22 Sep - 24 Sep	China Airlines
22 Sep - 26 Sep	China Airlines
24 Sep - 26 Sep	China Airlines
24 Sep - 27 Sep	China Airlines
22 Sep - 30 Sep	Qatar Airways
26 Sep - 30 Sep	Qatar Airways
24 Sep - 30 Sep	Qatar Airways
22 Sep - 29 Sep	Qatar Airways
26 Sep - 29 Sep	Qatar Airways
25 Sep - 28 Sep	Qatar Airways

Also check the deals for one-way flights from Ontario to Seoul 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.

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Cheapest return flights from Ontario to Seoul in September from 835€

Return flights