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$38+ Cheap flights from San Francisco to Ontario (SFO - ONT)

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 7/28. Fares are subject to change and may not be available on all flights or dates of travel.
SFO — ONT
Jul 5 — Jul 121
Sat 7/5
Sat 7/12
1 adult, Economy
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Cheapflights Tip: The best prices from San Francisco to Ontario are usually found in July or February, booked 89 days in advance, depart on a Monday or Saturday and return on a Friday

Cheap flight deals from San Francisco to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from San Francisco (SFO) to Ontario (ONT). 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 June 30, 2025.

Round-trip from

$57
(United Airlines)

One-way from

$38
(Kiwi.com)

Popular in

December

Cheapest in

July

Average price

$148

Good round-trip deal

$83 or less

Good one-way deal

$54 or less
From San Francisco to Ontario
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One-way flight from San Francisco to Ontario
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Highest demand for flights based on searches. 20% potential increase in price ($34 potential increase over avg. RT price).
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Cheapest flight prices on average. 8% potential price decrease ($10 potential savings vs. average RT price).
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Average for round-trip flights in June 2025
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Price to beat on a round-trip flight from San Francisco to Ontario.
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Price to beat on a one-way flight from San Francisco to Ontario.
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Find flight deals from San Francisco to Ontario

Cheapest flights from San Francisco to Ontario
Explore the most affordable flight options available from San Francisco to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 30, 2025.

This United Airlines deal was found by Cheapflights users on 6/28. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/164:16 pmSFO - ONT
Nonstop1h 27mUnited Airlines
Sat 8/26:10 amONT - SFO
Nonstop1h 27mUnited Airlines
Deal found 6/28$57
This Frontier deal was found by Cheapflights users on 6/28. 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.
Mon 7/2810:11 pmSFO - ONT
Nonstop1h 29mFrontier
Mon 8/49:47 pmONT - SFO
Nonstop1h 33mFrontier
Deal found 6/28$58

Cheapflights Fare Finder

Customize your flight search to find flights from San Francisco to Ontario 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 June 30, 2025.
Use the filters below to find and compare flights from San Francisco to Ontario that are best for you.

Fly from

San Francisco

Fly to

Ontario

Route

Depart

Return

Price

San FranciscoOntario

SFO - ONT

SFOONT

San Francisco

Wed 7/16

4:16 pm-5:43 pm

Nonstop1h 27m

Ontario

Sat 8/2

6:10 am-7:37 am

Nonstop1h 27m

$57

San FranciscoOntario

SFO - ONT

SFOONT

San Francisco

Mon 7/28

10:11 pm-11:40 pm

Nonstop1h 29m

Ontario

Mon 8/4

9:47 pm-11:20 pm

Nonstop1h 33m

$58

San FranciscoOntario

SFO - ONT

SFOONT

San Francisco

Mon 7/28

10:11 pm-11:40 pm

Nonstop1h 29m

$38

San FranciscoOntario

SFO - ONT

SFOONT

San Francisco

Tue 7/29

9:25 pm-10:52 pm

Nonstop1h 27m

$59

San FranciscoOntario

SFO - ONT

SFOONT

San Francisco

Tue 8/5

4:45 pm-9:00 pm

1 stop4h 15m

$76

San FranciscoOntario

SFO - ONT

SFOONT

San Francisco

Thu 7/10

3:11 pm-9:38 pm

1 stop6h 27m

$94

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/29

The best insider tips for San Francisco to Ontario flights

Snippets provided in this section are AI-generated based on a summarization of Cheapflights-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
Cheapflights partnered with top experts to bring you the best recommendations for your San Francisco to Ontario trip
Airports
SFO

Save time by using the SFO2Go program to order meals for pickup during busy times.

Read more about SFOby Harriet Baskas
ONT

Consider renting a car at ONT for convenient travel in the L.A. area.

Read more about ONTby Bill Fink
Our travel experts
Bill Fink

Bill Fink

Expert on ONT

Bill Fink

Bill Fink

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
Harriet Baskas

Harriet Baskas

Expert on SFO

Harriet Baskas

Harriet Baskas

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

Best time to book a flight from San Francisco to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from San Francisco 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 San Francisco to Ontario

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

Use this chart to determine the optimal time to book a round-trip flight from San Francisco to Ontario. Price data was last updated on June 27, 2025.

Booking 89 days in advance of your planned departure date is, on average, the best time to get cheap flights from San Francisco to Ontario. 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 San Francisco to Ontario?

Currently, August is the cheapest month in which you can book a flight from San Francisco to Ontario (average of $246). Flying from San Francisco to Ontario in March is currently the most expensive (average of $328). 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 SFO to ONT?

Find hourly flight availability from San Francisco to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 30, 2025.

Unlike in the afternoon, when flights are generally more expensive, you can save up to 28% on flights from San Francisco to Ontario by exploring options for tickets at noon.

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

Use this chart to determine the cheapest time to fly round-trip from San Francisco to Ontario. Price data was last updated on June 29, 2025.

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

Weekly flight availability from San Francisco to Ontario

Explore weekly flight availability from San Francisco to Ontario. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated June 30, 2025.

The most flights from SFO to ONT are scheduled on a Monday (8 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (3 on average).

Reviews of airlines servicing Ontario

Get insights into the airlines that provide service to Ontario. 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 Ontario. Reviews last updated June 30, 2025.
Peruse reviews from past customers who have flown with Southwest, United Airlines, and American Airlines from San Francisco to Ontario to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,278 reviews

Comfort

8.0

Boarding

8.2

Entertainment

7.6

Crew

8.6

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Southwest
8.0
Very good
4,278 reviews
Southwest
8.0
Very good
4,278 reviews

Comfort

8.0

Boarding

8.2

Entertainment

7.6

Crew

8.6

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
United Airlines
7.4
Good
8,852 reviews
Southwest
8.0
Very good
4,278 reviews

Comfort

8.0

Boarding

8.2

Entertainment

7.6

Crew

8.6

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,278 reviews

Comfort

8.0

Boarding

8.2

Entertainment

7.6

Crew

8.6

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Frontier
5.9
Fair
3,290 reviews
Southwest
8.0
Very good
4,278 reviews

Comfort

8.0

Boarding

8.2

Entertainment

7.6

Crew

8.6

Overall

8.0

Food

7.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.

Related info for your journey

Find useful and relevant information for your journey from San Francisco to Ontario. 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 San Francisco to Ontario?

    Ontario is the airport most travelers will use when flying to Ontario from San Francisco. Booking flights from San Francisco (SFO) to Ontario (ONT) should be relatively easy as there are 6 daily flights to Ontario from 5 different airlines. 1h 20m is how long a flight from San Francisco to Ontario will take if you book a nonstop flight.

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

    Within the past month, 81 users have taken a look at flights from San Francisco to Ontario.

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

    Flying on United Airlines is currently your cheapest option to Ontario, with prices starting at $57. Another option worth looking into is Frontier, starting at $58 round trip. You may be able to fly from San Francisco to Ontario for 57% less than the average price by searching for these airlines.

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

    To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $38. United Airlines flights start at $59 while deals on Southwest start at $76 one-way.

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

    No one likes to see their flight delayed. When booking a flight from San Francisco to Ontario consider choosing Copa Airlines (100%), SkyWest Airlines (92%) or Air Canada (89%) as they are the most reliable in getting you off to your destination on time.

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

    On average you can expect to pay $118 for a flight from San Francisco to Ontario. The cheapest flight overall is $28 while the most popular route, (San Francisco - Ontario) is currently priced at $64.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from San Francisco to Ontario 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 San Francisco to Ontario?

    Currently, August is the cheapest month in which you can book a flight from San Francisco to Ontario (average of $246). Flying from San Francisco to Ontario in March is currently the most expensive (average of $328). 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

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Top 5 airlines flying from San Francisco to Ontario

Discover the top 5 airlines that operate flights from San Francisco to Ontario. 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 June 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$32Average$89FlexibilityNo cancel feeOn-time65%
FrontierCheapest$37Average$99FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$58Average$229FlexibilityNo cancel feeOn-time69%
DeltaCheapest$58Average$159FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$107Average$197FlexibilityNo cancel feeOn-time75%

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