AirHint found the following cheapest return flights from Ontario (ONT) to San Francisco (SFO) in April 2026 (see full year).
Return flights
| 16 Apr - 19 Apr | United | direct |
Also check the deals for one-way flights from Ontario to San Francisco in April.
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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