Cheap flights from San Francisco to Ontario

One-way fares from $20 · SFO → ONT · prices found by travellers in the last 48 hours

Compare all dates Ontario → San Francisco
Cheapest fare
$20

Frontier Airlines · Wed, Dec 30

Cheapest month
December

from $20

Direct flights
Yes

Frontier Airlines and United Airlines

Flight time
1h 24m

600 km

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Cheapest month to fly from San Francisco to Ontario

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

  1. November 2026 $30
  2. December 2026 Cheapest $20
  3. January 2027 $61
  4. March 2027 $26
  5. April 2027 $223
  6. May 2027 $223
  7. June 2027 $249
  8. July 2027 $201
  9. September 2027 $236

Cheapest dates in December 2026

The lowest fares we've seen for each day, cheapest first.

Frontier Airlines
Depart21:56 Tue, Dec 8SFO → ONT 1h 27m · Direct
$20one way, per person
View deal
See every date in December 2026 →

Plan the rest of your trip to Ontario

Where to stay, what to do and getting around, from our travel partners.

Where to stay

Hotels in OntarioCompare places to stay on Booking.com Find hotels →

Things to do

Things to do in OntarioTours, attractions and day trips on Klook Explore →

Getting around

Airport transfer in OntarioPre-book a driver to meet you at arrivals, with Kiwitaxi Book a transfer → Car hire in OntarioCompare rental cars from major brands on EconomyBookings Compare cars →

About flights from San Francisco to Ontario

San Francisco (SFO) and Ontario (ONT) are about 600 km apart. Direct flights take around 1h 24m, and recent direct fares were with Frontier Airlines and United Airlines. Over the next few months, one-way fares start from $20, 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 San Francisco to Ontario?

The cheapest one-way fare we've seen recently is $20 with Frontier Airlines, departing Wednesday, December 30, 2026. Over the coming months, the lowest fare in each month ranges from $20 to $249.

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

December 2026 currently has the lowest fares, from $20 one way.

Are there direct flights from San Francisco to Ontario?

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

How long is the flight from San Francisco to Ontario?

A direct flight takes about 1h 24m. San Francisco and Ontario are around 600 km apart.

Which airlines fly from San Francisco to Ontario?

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

More cheap flights from San Francisco

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