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Ontario

$40+ Cheap flights from California to Ontario (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 9/2. Fares are subject to change and may not be available on all flights or dates of travel.
LAX — ONT
Aug 5 — Aug 121
Tue 8/5
Tue 8/12
1 adult, Economy
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Cheap flight deals from California to Ontario

Keep the following information in mind while searching for California to Ontario flight deals. Data was last updated July 31, 2025.

Round-trip from

$63
(Cheapflightsfares)

One-way from

$40
(Frontier)

Good round-trip deal

$89 or less

Good one-way deal

$59 or less
From California to Ontario
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One-way flight from California to Ontario
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Price to beat on a round-trip flight from California to Ontario.
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Price to beat on a one-way flight from California to Ontario.
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Find flight deals from California to Ontario

Cheapest flights from California to Ontario
Explore the most affordable flight options available from California to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 31, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 7/28. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/1610:11 pmSFO - ONT
Nonstop1h 29mFrontier
Mon 10/209:41 pmONT - SFO
Nonstop1h 32mFrontier
Deal found 7/28$63
This Frontier deal was found by Cheapflights users on 7/29. 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 8/110:43 amLAS - ONT
Nonstop1h 10mFrontier
Tue 8/57:00 amONT - LAS
Nonstop1h 11mFrontier
Deal found 7/29$78
This United Airlines deal was found by Cheapflights users on 7/29. 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.
Tue 8/2610:45 amSFO - ONT
Nonstop1h 28mUnited Airlines
Tue 9/26:50 pmONT - SFO
Nonstop1h 19mUnited Airlines
Deal found 7/29$97
This Southwest deal was found by Cheapflights users on 7/30. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/286:05 amOAK - ONT
Nonstop1h 25mSouthwest
Mon 9/15:50 amONT - OAK
Nonstop1h 20mSouthwest
Deal found 7/30$97
This Southwest deal was found by Cheapflights users on 7/31. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/219:55 amLAS - ONT
Nonstop1h 10mSouthwest
Mon 8/255:05 pmONT - LAS
Nonstop1h 10mSouthwest
Deal found 7/31$97
This Southwest deal was found by Cheapflights users on 7/30. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/302:10 pmSJC - ONT
1 stop6h 30mSouthwest
Tue 9/21:55 pmONT - SJC
Nonstop1h 15mSouthwest
Deal found 7/30$107
This FlightHub deal was found by Cheapflights users on 7/29. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/1211:58 amRNO - ONT
1 stop11h 52mFrontier
Wed 8/137:22 pmONT - RNO
1 stop16h 36mFrontier
Deal found 7/29$165
This CheapOair deal was found by Cheapflights users on 7/31. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/46:41 pmSMF - ONT
1 stop21h 39mFrontier
Wed 8/67:22 pmONT - SMF
1 stop20h 49mFrontier
Deal found 7/31$168
This CheapOair deal was found by Cheapflights users on 7/31. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/42:12 pmSJC - ONT
1 stop26h 08mFrontier
Wed 8/67:22 pmONT - SJC
1 stop22h 42mFrontier
Deal found 7/31$168
This Southwest deal was found by Cheapflights users on 7/31. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/2110:35 amSMF - ONT
Nonstop1h 25mSouthwest
Sun 8/248:25 pmONT - SMF
Nonstop1h 25mSouthwest
Deal found 7/31$186
This Delta deal was found by Cheapflights users on 7/31. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/235:09 pmSMF - ONT
1 stop5h 31mDelta
Wed 8/279:50 amONT - SMF
1 stop6h 22mDelta
Deal found 7/31$187
This United Airlines deal was found by Cheapflights users on 7/31. 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.
Tue 8/262:05 pmFAT - ONT
1 stop3h 32mUnited Airlines
Wed 9/31:42 pmONT - FAT
1 stop6h 06mUnited Airlines
Deal found 7/31$197

Cheapflights Fare Finder

 
Customize your flight search to find flights from California 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 July 31, 2025.
Use the filters below to find and compare flights from California to Ontario that are best for you.

Fly from

California

Fly to

Ontario

Route

Depart

Return

Price

San FranciscoOntario

SFO - ONT

SFOONT

San Francisco

Thu 10/16

10:11 pm-11:40 pm

Nonstop1h 29m

Ontario

Mon 10/20

9:41 pm-11:13 pm

Nonstop1h 32m

$63

Las VegasOntario

LAS - ONT

LASONT

Las Vegas Harry Reid Intl

Mon 8/18

7:45 pm-8:52 pm

Nonstop1h 07m

Ontario

Wed 8/20

8:00 am-9:13 am

Nonstop1h 13m

$78

San FranciscoOntario

SFO - ONT

SFOONT

San Francisco

Tue 8/26

10:45 am-12:13 pm

Nonstop1h 28m

Ontario

Tue 9/2

6:50 pm-8:09 pm

Nonstop1h 19m

$97

OaklandOntario

OAK - ONT

OAKONT

Oakland

Thu 8/28

6:05 am-7:30 am

Nonstop1h 25m

Ontario

Mon 9/1

5:50 am-7:10 am

Nonstop1h 20m

$97

Las VegasOntario

LAS - ONT

LASONT

Las Vegas Harry Reid Intl

Thu 8/21

9:55 am-11:05 am

Nonstop1h 10m

Ontario

Mon 8/25

5:05 pm-6:15 pm

Nonstop1h 10m

$97

San JoseOntario

SJC - ONT

SJCONT

San Jose

Sat 8/30

2:10 pm-8:40 pm

1 stop6h 30m

Ontario

Tue 9/2

1:55 pm-3:10 pm

Nonstop1h 15m

$107

RenoOntario

RNO - ONT

RNOONT

Reno

Tue 8/12

11:58 am-11:50 pm

1 stop11h 52m

Ontario

Wed 8/13

7:22 pm-11:58 am

1 stop16h 36m

$165

SacramentoOntario

SMF - ONT

SMFONT

Sacramento Intl

Mon 8/11

6:41 pm-4:20 pm

1 stop21h 39m

Ontario

Wed 8/13

7:22 pm-4:11 pm

1 stop20h 49m

$168

San JoseOntario

SJC - ONT

SJCONT

San Jose

Mon 8/11

2:12 pm-8:52 pm

1 stop6h 40m

Ontario

Sat 8/16

5:21 pm-11:22 am

1 stop18h 01m

$169

SacramentoOntario

SMF - ONT

SMFONT

Sacramento Intl

Thu 8/21

10:35 am-12:00 pm

Nonstop1h 25m

Ontario

Sun 8/24

8:25 pm-9:50 pm

Nonstop1h 25m

$186

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/29

Showing 1-10 of 60 results
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Best time to book a flight from California to Ontario

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

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

Currently, August is the cheapest month in which you can book a flight from California to Ontario (average of $246). Flying from California 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 CA to ONT?

Find hourly flight availability from California 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 July 31, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from California to Ontario as you normally would.

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 July 31, 2025.
See what other customers who have flown with Alaska Airlines, Southwest, and Delta from California to Ontario have to say. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Food

7.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Food

7.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,246 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Food

7.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,981 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Food

7.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.8
Good
2,611 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Food

7.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,900 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Overall

8.0

Crew

8.5

Boarding

8.1

Entertainment

7.1

Comfort

7.8

Food

7.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Related info for your journey

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

  • What airport do you fly into for flights to Ontario from California?

    Located just 3.1 mi from the city center, Ontario (ONT) is the airport most travelers will use when flying to Ontario from California.

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

    For one-way options, check prices for Frontier. According to our data, you can fly for as low as $40. Users have also found prices from $49 and $49 on United Airlines and Southwest, respectively.

  • What are the most popular routes from California to Ontario?

    When deciding which route to take from California to Ontario consider San Francisco - Ontario, Sacramento Intl - Ontario or San Jose - Ontario as they are the most popular.

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

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

  • How can I find direct flights from California to Ontario?

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

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

    Yes. Cheapflights offers flight deals from California 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 California to Ontario?

    Currently, August is the cheapest month in which you can book a flight from California to Ontario (average of $246). Flying from California 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

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for California to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
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Top 7 airlines flying from California to Ontario

Discover the top 7 airlines that operate flights from California 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 July 31, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$24Average$84FlexibilityNo cancel feeOn-time65%
FrontierCheapest$27Average$102FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$58Average$247FlexibilityNo cancel feeOn-time69%
DeltaCheapest$58Average$181FlexibilityNo cancel feeOn-timeN/A
Alaska AirlinesCheapest$59Average$241FlexibilityNo cancel feeOn-time75%
SouthwestCheapest$145Average$275FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$186Average$221FlexibilityNo cancel feeOn-time71%

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