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Cheap flights from Ontario to San Francisco from £42

ONT — SFO
4 Dec — 11 Dec1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Ontario to San Francisco are usually found in August or October, booked 73 days in advance, depart on a Tuesday or Monday and return on a Monday

Cheap flight deals from Ontario to San Francisco

Enter your travel dates to find the best prices.

Cheapest flights from Ontario to San Francisco

Sat 5/1211:00 -
1 stop8h 37m
Mon 7/1221:16 -
1 stop14h 35m
Deal found 3/11£72
Tue 15/1219:26 -
Nonstop1h 35m
Tue 22/1216:11 -
1 stop5h 42m
Deal found 31/10£83
Mon 23/1106:00 -
Nonstop1h 30m
Thu 26/1114:00 -
Nonstop1h 24m
Deal found 1/11£87
Sat 19/1206:00 -
Nonstop1h 33m
Sat 19/1221:30 -
Nonstop1h 23m
Deal found 3/11£97
Fri 4/1206:00 -
Nonstop1h 30m
Sun 6/1208:45 -
Nonstop1h 28m
Deal found 30/10£103
Sat 5/1213:25 -
1 stop3h 55m
Wed 9/1210:25 -
1 stop5h 45m
Deal found 2/11£113
Sun 13/1206:00 -
Nonstop1h 30m
Sun 13/1208:45 -
Nonstop1h 28m
Deal found 2/11£115
Fri 27/1120:31 -
Nonstop1h 33m
Mon 30/1121:11 -
1 stop21h 00m
Deal found 3/11£119
Sat 5/1213:05 -
2 stops7h 05m
Tue 8/1213:30 -
2 stops6h 25m
Deal found 2/11£120
Fri 18/1221:35 -
2 stops11h 15m
Fri 25/1205:05 -
1 stop4h 15m
Deal found 3/11£121
Mon 21/1218:27 -
Nonstop1h 51m
Thu 24/1216:10 -
Nonstop1h 36m
Deal found 3/11£122

Find flight deals from Ontario to San Francisco

Round-trip from

£72

One-way from

£42

Popular in

February

Cheapest in

August

Average price

£159

Good round-trip deal

£139 or less
Frontier
  • Frontier
  • 5/12-7/12
  • 2 total stops
  • 23h 12m total
  • Ontario to San Francisco
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Frontier
  • Frontier
  • 19/12-31/12
  • 1 total stop
  • 8h 48m total
  • Ontario to San Francisco
Search Deals
Highest demand for flights based on searches. 17% potential increase in price (£27 potential increase over avg. return price).
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Cheapest flight prices on average. 3% potential price decrease (£5 potential savings vs. average return price).
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Average for round-trip flights in November 2026
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Price to beat on a round-trip flight from Ontario to San Francisco.
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Cheapflights Fare Finder

 
Use the filters below to find and compare flights from Ontario to San Francisco that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Sun 24/1

06:00-07:33

Nonstop1h 33m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£74
Fastest return journey

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Wed 25/11

06:00-07:30

Nonstop1h 30m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£78

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Wed 3/3

18:37-20:10

Nonstop1h 33m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£78

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Sat 16/1

15:59-17:50

Nonstop1h 51m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£78

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Thu 31/12

06:00-07:33

Nonstop1h 33m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£78

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Fri 18/12

16:00-17:50

Nonstop1h 50m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£78

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Wed 16/12

16:17-17:50

Nonstop1h 33m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£78

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Sat 19/12

06:00-07:33

Nonstop1h 33m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£78

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Wed 13/1

14:00-15:33

Nonstop1h 33m

San Francisco

Wed 31/12

00:00-00:00

Nonstop0h 00m

£78

OntarioSan Francisco

ONT Ontario - SFO San Francisco

ONTSFO

Ontario

Thu 26/11

12:30-14:00

Nonstop1h 30m

San Francisco

Fri 27/11

18:50-20:15

Nonstop1h 25m

£87

Flights are sorted by cheapest return flights first.

Deals found on 3/11

Showing 1-10 of 20 resultsSorted by cheapest first
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Best time to book a flight from Ontario to San Francisco

Have a flexible travel schedule? Discover the best time to fly to San Francisco from Ontario with our price prediction graph.
Estimated return price

Cheapflights Insights

Everything you need to know about your flight from Ontario to San Francisco

How far ahead should I book a flight from Ontario to San Francisco?

The best time to book flights from Ontario to San Francisco is 72 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

What is the cheapest month to book a flight from Ontario to San Francisco?

Currently, August is the cheapest month in which you can book a flight from Ontario to San Francisco (average of £121). Flying from Ontario to San Francisco in February is currently the most expensive (average of £227). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from ONT to SFO?

One of the essential ways to save on airfare from Ontario to San Francisco is to remain as flexible as possible. Flights that are at midday tend to be the most expensive. A flight in the morning could potentially save you up to 94% on airfare.

How much does it cost for a return flight from Ontario to San Francisco?

Airfare is below average for this route at the moment.

Ontario to San Francisco flights typically cost between £109 and £206 in December.
The cheapest return price found within the last 5 days was £72 on Frontier (5 Dec–7 Dec).

Related info for your journey

  • How popular is this Ontario to San Francisco flight route?

    This flight path from Ontario to San Francisco was viewed by 15 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • How long is the flight from Ontario to San Francisco?

    Departing from Ontario to San Francisco will take you 1h 30m. The distance from Ontario to San Francisco is about 363 mi. Generally, flights for this route are direct.

  • What are the most reliable airlines from Ontario to San Francisco?

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Ontario to San Francisco on time: Emirates (89%), SkyWest Airlines (82%), United Airlines (74%).

  • Can I find deals for flights from Ontario to San Francisco that include hotel bookings?

    Yes. In addition to deals on Ontario to San Francisco flights, Cheapflights offers holiday packages that include both flights and hotel.

  • How can I find direct flights from Ontario to San Francisco?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to San Francisco.

  • Can I find deals for business class flights from Ontario to San Francisco?

    Yes. Cheapflights offers flight deals from Ontario to San Francisco by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Ontario to San Francisco?

    Currently, August is the cheapest month in which you can book a flight from Ontario to San Francisco (average of £121). Flying from Ontario to San Francisco in February is currently the most expensive (average of £227). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Travelling to a place near San Francisco?

Book flights to San Francisco if you plan to visit one of these locations
San Bruno
Santa Cruz
Roseville
Newark
Sunnyvale
Bodega Bay

Browse thousands of different options on Cheapflights for your next trip

Fly with Cheapflights

How does Cheapflights help users find flights from Ontario to San Francisco?

When you search for this flight from Ontario to San Francisco, Cheapflights searches on 900+ travel sites to save you time finding great flight deals online. Additionally, we offer filter features so you can choose a preferred cabin class or airline, see different price ranges, and much more so you can book the flight for you.

Why should you use Cheapflights to find cheap flight tickets from Ontario to San Francisco?

Cheapflights simply makes it quick and affordable to book flights from Ontario to San Francisco by bringing together all flight options from hundreds of airlines and agencies online — and put it in one place for you to choose from. Plus, Cheapflights is 100% free to use for all.

Can Cheapflights find flights from Ontario to San Francisco with no change fees?

Cheapflights does show flights with no change fees to all users. To see these options for flights from Ontario to San Francisco, users can toggle the no change fees filter when performing a flight search.

Can Cheapflights notify me if prices for flights from Ontario to San Francisco become cheaper?

Of course! You can now track prices for flights from Ontario to San Francisco and get an alert from Cheapflights when they change. Have a valid email address ready and click the bell icon next to the flight deals above to set up your price alerts.

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