HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
San Francisco

$78+ Cheap flights from Ontario to San Francisco (ONT - SFO)

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 4/23. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — SFO
Mar 5 — Mar 121
Thu 3/5
Thu 3/12
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Ontario to San Francisco with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.
Cheapflights Tip: The best prices from Ontario to San Francisco are usually found in May or April, booked 37 days in advance, depart on a Friday or Thursday and return on a Monday

Cheap flight deals from Ontario to San Francisco

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 February 3, 2026.

This Frontier deal was found by Cheapflights users on 2/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 3/279:06 am
ONT
-
SFO
Nonstop1h 42m
Frontier
Fri 4/38:48 am
SFO
-
ONT
Nonstop1h 32m
Frontier
Deal found 2/2$143
This Expedia deal was found by Cheapflights users on 2/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/38:40 am
ONT
-
SFO
1 stop13h 21m
Frontier
Wed 4/110:14 pm
SFO
-
ONT
1 stop9h 50m
Frontier
Deal found 2/2$144
This Trip.com deal was found by Cheapflights users on 2/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/76:20 am
ONT
-
SFO
1 stop13h 50m
Frontier
Mon 4/138:48 am
SFO
-
ONT
Nonstop1h 32m
Frontier
Deal found 2/2$145
This Frontier deal was found by Cheapflights users on 2/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 2/263:24 pm
ONT
-
SFO
1 stop4h 15m
Frontier
Mon 3/29:03 am
SFO
-
ONT
1 stop4h 08m
Frontier
Deal found 2/2$147
This Mytrip deal was found by Cheapflights users on 2/3. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 3/69:06 am
ONT
-
SFO
Nonstop1h 42m
Frontier
Mon 3/96:00 am
SFO
-
ONT
1 stop17h 59m
Frontier
Deal found 2/3$149
This Mytrip deal was found by Cheapflights users on 2/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 3/26:43 pm
ONT
-
SFO
1 stop23h 37m
Frontier
Wed 3/47:15 pm
SFO
-
ONT
1 stop23h 12m
Frontier
Deal found 2/2$150
This Frontier deal was found by Cheapflights users on 2/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/242:23 pm
ONT
-
SFO
1 stop4h 14m
Frontier
Fri 4/38:48 am
SFO
-
ONT
Nonstop1h 32m
Frontier
Deal found 2/2$151
This Super.com deal was found by Cheapflights users on 2/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 3/42:06 pm
ONT
-
SFO
1 stop19h 47m
Frontier
Wed 3/119:04 pm
SFO
-
ONT
1 stop26h 55m
Frontier
Deal found 2/2$152
This Frontier deal was found by Cheapflights users on 2/2. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 4/235:33 pm
ONT
-
SFO
1 stop6h 49m
Frontier
Sun 4/269:23 am
SFO
-
ONT
Nonstop1h 29m
Frontier
Deal found 2/2$155
This Kiwi.com deal was found by Cheapflights users on 2/1. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 3/38:40 am
ONT
-
SFO
1 stop13h 21m
Frontier
Fri 3/66:00 am
SFO
-
ONT
1 stop17h 59m
Frontier
Deal found 2/1$156

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 February 3, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$143
(Frontier)

One-way from

$78
(Super.com)

Popular in

November

Cheapest in

May

Average price

$138

Good round-trip deal

$261 or less

Good one-way deal

$131 or less
Provider with most accurate pricing for Ontario-San Francisco flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ontario-San Francisco flights.
Search Deals
From Ontario to San Francisco
Search Deals
One-way flight from Ontario to San Francisco
Search Deals
Highest demand for flights based on searches. 21% potential increase in price ($39 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($6 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in February 2026
Search Deals
Price to beat on a round-trip flight from Ontario to San Francisco.
Search Deals
Price to beat on a one-way flight from Ontario to San Francisco.
Search Deals

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 2,558,603 searches. Data last updated February 3, 2026.
Use the filters below to find and compare flights from Ontario to San Francisco that are best for you.

Fly from

Ontario

Fly to

San Francisco

Route

Depart

Return

Price

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 5/6

2:25 pm-10:05 pm

2 stops7h 40m

San Francisco

Wed 5/13

10:30 am-3:05 pm

1 stop4h 35m

$244

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Mon 5/11

6:00 am-7:29 am

Nonstop1h 29m

San Francisco

Wed 5/13

4:15 pm-5:52 pm

Nonstop1h 37m

$252

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 3/25

6:37 pm-8:10 pm

Nonstop1h 33m

San Francisco

Wed 4/15

10:44 am-12:14 pm

Nonstop1h 30m

$254

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 3/18

6:15 am-7:48 am

Nonstop1h 33m

San Francisco

Wed 4/1

10:44 am-12:14 pm

Nonstop1h 30m

$254

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 3/13

1:40 pm-3:13 pm

Nonstop1h 33m

San Francisco

Fri 3/20

9:30 pm-10:57 pm

Nonstop1h 27m

$259

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 3/20

5:25 pm-12:50 am

1 stop7h 25m

San Francisco

Tue 3/24

6:25 am-10:25 am

1 stop4h 00m

$269

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 4/8

3:45 pm-11:15 pm

2 stops7h 30m

San Francisco

Wed 4/15

5:40 am-1:45 pm

2 stops8h 05m

$269

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Sat 5/16

6:00 am-7:29 am

Nonstop1h 29m

San Francisco

Wed 5/20

9:23 pm-10:59 pm

Nonstop1h 36m

$275

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Thu 3/26

4:25 pm-9:35 pm

1 stop5h 10m

San Francisco

Mon 3/30

5:40 pm-10:05 pm

1 stop4h 25m

$279

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 3/17

1:40 pm-3:13 pm

Nonstop1h 33m

San Francisco

Tue 3/24

10:50 am-12:18 pm

Nonstop1h 28m

$279

Flights are sorted by cheapest round-trip flights first.

Deals found on 2/1

Showing 1-10 of 22 results
1
2
3

Compare providers for flights from Ontario to San Francisco

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to San Francisco in February.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
CheapOairPrice Accuracy3 starsTrust Score*3 stars
CheapflightsfaresPrice Accuracy2 starsTrust Score*2 stars
JustAirTicketPrice Accuracy-Trust Score*1 star
CheapTicketsDealPrice Accuracy3 starsTrust Score*3 stars
CheapfaremartPrice Accuracy-Trust Score*1 star

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Ontario-San Francisco flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-San Francisco flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-San Francisco flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-San Francisco flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-San Francisco flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

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?

Use this chart to determine the optimal time to book a round-trip flight from Ontario to San Francisco. Price data was last updated on January 30, 2026.

Booking 37 days in advance of your planned departure date is, on average, the best time to get cheap flights from Ontario to San Francisco. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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

Currently, February is the cheapest month in which you can book a flight from Ontario to San Francisco (average of $19). Flying from Ontario to San Francisco in November is currently the most expensive (average of $62). 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 February 3, 2026.

One of the essential ways to save on airfare from Ontario to San Francisco is to remain as flexible as possible. Flights that are in the afternoon tend to be the most expensive. A flight in the evening could potentially save you up to 66% on airfare.

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

Use this chart to determine the cheapest time to fly round-trip from Ontario to San Francisco. Price data was last updated on January 31, 2026.

Travelers seeking maximum savings on their Ontario to San Francisco flight should consider departing on Saturday evenings when fares are most often at their lowest. Monday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

The best insider tips for Ontario to San Francisco flights

AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your Ontario to San Francisco trip
Our travel experts
Harriet Baskas

Harriet Baskas

Expert on United Airlines and SFO

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Read more
Marisa Garcia

Marisa Garcia

Expert on Frontier

Marisa knows planes inside and out, spending 16 years working on aircraft in hangars at airports around the world. She is an aviation industry expert, specialized in airline interiors and regulations. Ten years ago, she pivoted to journalism. She shares her insights in leading aviation, travel, and business publications and on her site FlightChic.

Read more
Bill Fink

Bill Fink

Expert on ONT

Bill is an award-winning travel writer with extensive credits covering airlines and the aviation industry for publications including AARP, AFAR, The Points Guy and Yahoo. Based in Portland, Oregon, Bill has traveled to more than 75 countries - and been late for his flight in most of them. He once achieved top-level frequent flier status for all of American, Delta and United Airlines during a single year.

Read more

Reviews of airlines servicing San Francisco

Get insights into the airlines that provide service to San Francisco. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to San Francisco. Reviews last updated February 3, 2026.
See what other customers who have flown with Alaska Airlines, Southwest, and United Airlines from Ontario to San Francisco have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
11,831 reviews

Crew

8.5

Entertainment

7.0

Boarding

8.1

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
Alaska Airlines
8.0
Very good
11,831 reviews
Alaska Airlines
8.0
Very good
11,831 reviews

Crew

8.5

Entertainment

7.0

Boarding

8.1

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
Southwest
8.0
Very good
4,273 reviews
Alaska Airlines
8.0
Very good
11,831 reviews

Crew

8.5

Entertainment

7.0

Boarding

8.1

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
United Airlines
7.4
Good
9,231 reviews
Alaska Airlines
8.0
Very good
11,831 reviews

Crew

8.5

Entertainment

7.0

Boarding

8.1

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading
Frontier
5.7
Fair
3,052 reviews
Alaska Airlines
8.0
Very good
11,831 reviews

Crew

8.5

Entertainment

7.0

Boarding

8.1

Food

7.1

Overall

8.0

Comfort

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,Jan 2026

STS - LAX

Enjoyed staff assistance from ticking thru tsa , boarding and in the plane Couldn’t pick a seat except upgrading

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.

  • What airports do I use to fly from Ontario to San Francisco?

    To fly from Ontario to San Francisco, you need to book a flight from Ontario (ONT) to San Francisco (SFO). Nonstop flights to San Francisco from Ontario take 1h 25m on average. When it comes time to book airfare, you have a few options: there are 5 outbound flights from Ontario to San Francisco offered by 4 different airlines.

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

    This flight path from Ontario to San Francisco was viewed by 116 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?

    A quick flight from Ontario to San Francisco can take about 1h 29m. Southwest provides one of the quickest options available for as low as $252. The distance from Ontario to San Francisco is about 363 mi. This flight may include one or multiple stops.

  • What are the cheapest airlines flying from Ontario to San Francisco round-trip?

    Flying on Frontier is currently your cheapest option to San Francisco, with prices starting at $31. Additional round-trip tickets that might be worth considering are offered by United Airlines and Alaska Airlines, with the lowest prices starting at $58 and $67, respectively. You may be able to fly from Ontario to San Francisco for 78% less than the average price by searching for these airlines.

  • What are the cheapest airlines to fly from Ontario to San Francisco one-way?

    The cheapest airline one-way is Frontier, with whom users have recently found tickets for as low as $27. However, be on the lookout for offers from United Airlines and Delta, as they are both options that can get you from Ontario to San Francisco for a low price.

  • 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: United Airlines (86%), SkyWest Airlines (82%), Air Canada (74%).

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

    On average you can expect to pay $802 for a flight from Ontario to San Francisco. The cheapest flight overall is $76 while the most popular route, (Ontario - San Francisco) is currently priced at $98.

  • 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, February is the cheapest month in which you can book a flight from Ontario to San Francisco (average of $19). Flying from Ontario to San Francisco in November is currently the most expensive (average of $62). 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

Traveling to a place near San Francisco?

Book flights to San Francisco if you plan to visit one of these locations
South San Francisco
Santa Cruz
Santa Clara
Roseville
Livermore
Watsonville
San Bruno
Daly City
Sunnyvale
Turlock
Vacaville
San Carlos
San Ramon
San Lorenzo
Davis
Hollister
Redwood City
Manteca
Union City
Elk Grove

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Ontario to San Francisco

See prices for flight routes from nearby airports that may be better suited for you.
San Francisco to Las Vegas flights
Los Angeles to San Francisco flights
San Francisco to Los Angeles flights
Los Angeles to Las Vegas flights
San Francisco to Santa Ana flights
Santa Ana to San Francisco flights
San Jose to Los Angeles flights
San Francisco to Ontario flights
Burbank to Las Vegas flights
Santa Ana to Las Vegas flights
San Francisco to Burbank flights
Los Angeles to San Jose flights
San Jose to Las Vegas flights
San Francisco to San Diego flights
Burbank to San Francisco flights
Sacramento to Las Vegas flights
San Diego to Las Vegas flights
San Francisco to Palm Springs flights
Ontario to Las Vegas flights
Sacramento to Los Angeles flights
Los Angeles to Sacramento flights
San Jose to San Diego flights
San Jose to Santa Ana flights
San Diego to San Francisco flights
Oakland to Las Vegas flights
Santa Ana to San Jose flights
Oakland to San Diego flights
San Jose to Ontario flights
Las Vegas to Los Angeles flights
Ontario to San Jose flights
Los Angeles to Reno flights
Sacramento to San Diego flights
Sacramento to Ontario flights
Santa Rosa to Las Vegas flights
Burbank to San Jose flights
San Diego to San Jose flights
Las Vegas to San Francisco flights
Las Vegas to Burbank flights
San Jose to Burbank flights
Fresno to Las Vegas flights
Las Vegas to Santa Ana flights
Sacramento to Santa Ana flights
Ontario to Sacramento flights
Oakland to Los Angeles flights
Reno to Los Angeles flights
Reno to Las Vegas flights
Sacramento to Burbank flights
San Francisco to Long Beach flights
Santa Ana to Sacramento flights

Top 4 airlines flying from Ontario to San Francisco

Discover the top 4 airlines that operate flights from Ontario to San Francisco. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated February 3, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$31Average$101FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$58Average$184FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$67Average$173FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$176Average$286FlexibilityNo cancel feeOn-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.