Cheap flights from Ontario to San Francisco

One-way fares from $19 · ONT → SFO · prices found by travellers in the last 48 hours

Compare all dates San Francisco → Ontario
Cheapest fare
$19

Frontier Airlines · Tue, Dec 8

Cheapest month
December

from $19

Direct flights
Yes

Frontier Airlines and United Airlines

Flight time
1h 29m

600 km

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Cheapest month to fly from Ontario to San Francisco

Lowest one-way fare per person in each month. Choose a month to see every date.

  1. November 2026 $35
  2. December 2026 Cheapest $19
  3. January 2027 $159
  4. February 2027 $70
  5. March 2027 $151
  6. May 2027 $239
  7. June 2027 $213
  8. July 2027 $242
  9. August 2027 $208

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Getting around

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About flights from Ontario to San Francisco

Ontario (ONT) and San Francisco (SFO) are about 600 km apart. Direct flights take around 1h 29m, and recent direct fares were with Frontier Airlines and United Airlines. Over the next few months, one-way fares start from $19, and December 2026 is currently the cheapest month to fly.

These prices come from searches travellers made in the last 48 hours, so they move quickly. If you see a good fare, it's worth booking soon. FlightsExp is free to use: you book directly with our travel partner.

Frequently asked questions

How much is a flight from Ontario to San Francisco?

The cheapest one-way fare we've seen recently is $19 with Frontier Airlines, departing Tuesday, December 8, 2026. Over the coming months, the lowest fare in each month ranges from $19 to $242.

What is the cheapest month to fly from Ontario to San Francisco?

December 2026 currently has the lowest fares, from $19 one way.

Are there direct flights from Ontario to San Francisco?

Yes. Recent direct fares were with Frontier Airlines and United Airlines.

How long is the flight from Ontario to San Francisco?

A direct flight takes about 1h 29m. Ontario and San Francisco are around 600 km apart.

Which airlines fly from Ontario to San Francisco?

Recent fares on this route were with Frontier Airlines, Southwest Airlines and United Airlines.

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