Cheapest one-way flights from Ontario to San Francisco in September from $55

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

One-Way flights

11 Sep Frontier Airlines direct
15 Sep Frontier Airlines direct
12 Sep Frontier Airlines direct
18 Sep Frontier Airlines direct
25 Sep Frontier Airlines direct
26 Sep Frontier Airlines direct
03 Sep United direct
02 Sep United direct
30 Sep Southwest Airlines
17 Sep Southwest Airlines

Also check the deals for return flights from Ontario to San Francisco 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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