Cheapest return flights from San Francisco to Ontario in September from $89

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

Return flights

05 Sep - 08 Sep Frontier Airlines direct
12 Sep - 14 Sep Frontier Airlines direct
19 Sep - 22 Sep Frontier Airlines direct
05 Sep - 07 Sep Frontier Airlines direct
08 Sep - 15 Sep Frontier Airlines direct
07 Sep - 08 Sep Frontier Airlines direct
07 Sep - 11 Sep Frontier Airlines direct
22 Sep - 26 Sep Frontier Airlines direct
04 Sep - 08 Sep Frontier Airlines direct
20 Sep - 25 Sep Frontier Airlines
11 Sep - 02 Oct Southwest Airlines
26 Sep - 01 Oct Southwest Airlines
28 Sep - 05 Oct Southwest Airlines

Also check the deals for one-way flights from San Francisco to Ontario in September.

Skyscanner

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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