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Cheap flights from Ontario to San Francisco from C$ 107

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 20/5. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SFO
25 May — 1 Jun1
1 adult
1 adult, Economy, 0 bags
Cheapflights Tip: The best prices from Ontario to San Francisco are usually found in May or June, booked 67 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
Explore the most affordable flight options available from Ontario to San Francisco. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 25 April 2026.

Fri 15/58:17 p.m.
ONT
-
SFO
Nonstop1h 38m
Frontier
Mon 18/59:19 a.m.
SFO
-
ONT
Nonstop1h 32m
Frontier
Deal found 20/4C$ 185
Tue 9/66:00 a.m.
ONT
-
SFO
Nonstop1h 25m
United Airlines
Tue 16/69:00 p.m.
SFO
-
ONT
Nonstop1h 37m
United Airlines
Deal found 25/4C$ 188
Tue 19/56:00 a.m.
ONT
-
SFO
Nonstop1h 29m
United Airlines
Tue 26/59:00 p.m.
SFO
-
ONT
Nonstop1h 37m
United Airlines
Deal found 21/4C$ 212
Wed 20/56:00 a.m.
ONT
-
SFO
Nonstop1h 29m
United Airlines
Mon 25/510:40 a.m.
SFO
-
ONT
Nonstop1h 32m
United Airlines
Deal found 24/4C$ 215
Thu 14/56:59 p.m.
ONT
-
SFO
Nonstop1h 29m
United Airlines
Tue 19/54:15 p.m.
SFO
-
ONT
Nonstop1h 37m
United Airlines
Deal found 23/4C$ 227
Fri 3/78:36 p.m.
ONT
-
SFO
Nonstop1h 37m
Frontier
Mon 6/79:31 a.m.
SFO
-
ONT
Nonstop1h 27m
Frontier
Deal found 21/4C$ 234
Tue 9/66:35 p.m.
ONT
-
SFO
1 stop4h 40m
Southwest
Wed 10/65:00 a.m.
SFO
-
ONT
1 stop4h 15m
Southwest
Deal found 21/4C$ 240
Sat 16/510:43 a.m.
ONT
-
SFO
Nonstop1h 29m
United Airlines
Mon 18/510:52 a.m.
SFO
-
ONT
Nonstop1h 30m
United Airlines
Deal found 24/4C$ 242
Tue 15/93:35 p.m.
ONT
-
SFO
1 stop6h 05m
Southwest
Tue 22/91:35 p.m.
SFO
-
ONT
2 stops7h 20m
Southwest
Deal found 23/4C$ 248
Tue 18/83:34 p.m.
ONT
-
SFO
1 stop4h 22m
Frontier
Wed 19/811:12 a.m.
SFO
-
ONT
Nonstop1h 30m
Frontier
Deal found 25/4C$ 252

Find flight deals from Ontario to San Francisco

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to San Francisco (SFO). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 25 April 2026.

Round-trip from

C$ 185

One-way from

C$ 107

Popular in

February

Cheapest in

May

Average price

C$ 287

Good round-trip deal

C$ 665 or less

Good one-way deal

C$ 314 or less
Frontier
  • Frontier
  • 15/5-18/5
  • Nonstop
  • 3h 10m total
  • Ontario to San Francisco
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United Airlines
  • United Airlines
  • 20/5
  • Nonstop
  • 1h 30m total
  • Ontario to San Francisco
Search Deals
Highest demand for flights based on searches. 30% potential increase in price (C$ 157 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease (C$ 20 potential savings vs. average RT price).
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Average for round-trip flights in April 2026
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Price to beat on a round-trip flight from Ontario to San Francisco.
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Price to beat on a one-way flight from Ontario to San Francisco.
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Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to San Francisco that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 629,999 searches. Data last updated 25 April 2026.
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 round-trip

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 11/8

6:50 a.m.-1:15 p.m.

1 stop6h 25m

San Francisco

Fri 21/8

5:10 a.m.-11:25 a.m.

1 stop6h 15m

C$ 319

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Sat 30/5

1:40 p.m.-3:05 p.m.

Nonstop1h 25m

San Francisco

Mon 1/6

9:00 p.m.-10:37 p.m.

Nonstop1h 37m

C$ 339

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 30/9

6:05 a.m.-7:32 a.m.

Nonstop1h 27m

San Francisco

Sun 4/10

9:25 p.m.-10:59 p.m.

Nonstop1h 34m

C$ 368

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 12/5

1:30 p.m.-3:00 p.m.

Nonstop1h 30m

San Francisco

Fri 15/5

8:10 a.m.-9:41 a.m.

Nonstop1h 31m

C$ 387

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 1/7

4:35 p.m.-11:25 p.m.

1 stop6h 50m

San Francisco

Thu 2/7

5:30 a.m.-11:20 a.m.

1 stop5h 50m

C$ 396

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Thu 1/10

6:05 a.m.-7:32 a.m.

Nonstop1h 27m

San Francisco

Mon 5/10

4:10 p.m.-5:51 p.m.

Nonstop1h 41m

C$ 409

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 15/5

1:30 p.m.-2:59 p.m.

Nonstop1h 29m

San Francisco

Fri 15/5

9:23 p.m.-10:59 p.m.

Nonstop1h 36m

C$ 409

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 11/9

9:01 a.m.-10:28 a.m.

Nonstop1h 27m

San Francisco

Mon 14/9

4:40 p.m.-6:11 p.m.

Nonstop1h 31m

C$ 409

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Sat 16/5

10:43 a.m.-12:12 p.m.

Nonstop1h 29m

San Francisco

Mon 18/5

8:10 a.m.-9:41 a.m.

Nonstop1h 31m

C$ 412
Quickest round-trip

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Thu 28/5

1:50 p.m.-3:15 p.m.

Nonstop1h 25m

San Francisco

Mon 1/6

10:40 a.m.-12:12 p.m.

Nonstop1h 32m

C$ 415

Flights are sorted by cheapest round-trip flights first.

Deals found on 20/4

Showing 1-10 of 22 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 round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

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?

To ensure you get the cheapest price possible for a flight from Ontario to San Francisco, you should look to book at least 66 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

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

Currently, May is the cheapest month in which you can book a flight from Ontario to San Francisco (average of C$ 159). Flying from Ontario to San Francisco in February is currently the most expensive (average of C$ 408). 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?

Find hourly flight availability from Ontario to San Francisco. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 25 April 2026.

It’s typically best to fly out from Ontario to San Francisco in the evening. Doing so could potentially save you 93% on the flight price compared to flying in the afternoon, which is usually more expensive.

How much does it cost to fly round-trip from Ontario to San Francisco?

Related info for your journey

Find useful and relevant information for your journey from Ontario to San Francisco. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

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

    Within the past month, 7 users have taken a look at flights from Ontario to San Francisco.

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

    There are many flights that can get you from Ontario to San Francisco in 1h 29m. Fly via Frontier or United Airlines to get the fastest option. The distance from Ontario to San Francisco is about 584 km. All flights are typically direct.

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

    No one likes to see their flight delayed. When booking a flight from Ontario to San Francisco consider choosing SkyWest Airlines (100%), Emirates (88%) or Copa Airlines (84%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Ontario to San Francisco?

    While on average a flight from Ontario to San Francisco is generally C$ 546, our data shows the cheapest flight currently is C$ 301. When looking at the most popular route, (Ontario - San Francisco), you can expect to pay C$ 1,120 for that flight.

  • 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 vacation 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, May is the cheapest month in which you can book a flight from Ontario to San Francisco (average of C$ 159). Flying from Ontario to San Francisco in February is currently the most expensive (average of C$ 408). 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
Burlingame
San Bruno
Roseville
Livermore
South San Francisco
Novato
Santa Clara
Vallejo

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

Users can book flights with no change fees policies with our dedicated filters. Book flights from Ontario to San Francisco flexibly with Cheapflights today.

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

Not ready to book yet? You can track prices for flights from Ontario to San Francisco on Cheapflights with our Price Alert feature and get notified when better prices are available.

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