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

Return flights

24 Sep - 15 Oct	Delta
25 Sep - 02 Oct	Delta
28 Sep - 11 Oct	China Airlines
22 Sep - 26 Sep	STARLUX Airlines
26 Sep - 17 Oct	STARLUX Airlines
24 Sep - 06 Oct	STARLUX Airlines
24 Sep - 08 Oct	STARLUX Airlines
27 Sep - 27 Oct	STARLUX Airlines
29 Sep - 06 Oct	STARLUX Airlines
27 Sep - 04 Oct	STARLUX Airlines
27 Sep - 20 Oct	STARLUX Airlines
23 Sep - 28 Sep	China Airlines
24 Sep - 26 Sep	China Airlines
23 Sep - 29 Sep	China Airlines
25 Sep - 28 Sep	China Airlines
25 Sep - 30 Sep	China Airlines

Also check the deals for one-way flights from Ontario to Bangkok 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 Bangkok in September from 604€

Return flights