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Ontario

$52+ Cheap flights from Chicago (CHI) 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 2/23. Fares are subject to change and may not be available on all flights or dates of travel.
CHI — ONT
Jan 11 — Jan 181
Sun 1/11
Sun 1/18
1 adult, Economy
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Find cheap flights from Chicago to Ontario 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

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3. Compare prices and book

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Cheapflights Tip: The best prices from Chicago to Ontario are usually found in October or February, booked 9 days in advance, depart on a Thursday or Tuesday and return on a Thursday

Cheap flight deals from Chicago to Ontario

Cheapest flights from Chicago to Ontario
Explore the most affordable flight options available from Chicago to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 12, 2025.

This CheapOair deal was found by Cheapflights users on 12/11. 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.
Thu 12/258:21 pmORD - ONT
1 stop23h 09mFrontier
Thu 1/296:20 amONT - ORD
1 stop10h 11mFrontier
Deal found 12/11$237
This CheapOair deal was found by Cheapflights users on 12/11. 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.
Thu 12/258:21 pmORD - ONT
1 stop23h 09mFrontier
Mon 1/126:00 amONT - ORD
1 stop10h 45mFrontier
Deal found 12/11$254
This Frontier deal was found by Cheapflights users on 12/9. 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 12/1512:35 pmMDW - ONT
1 stop6h 57mFrontier
Fri 1/96:00 amONT - MDW
1 stop6h 05mFrontier
Deal found 12/9$268
This Mytrip deal was found by Cheapflights users on 12/10. 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.
Tue 12/304:47 pmORD - ONT
1 stop26h 43mFrontier
Thu 1/16:00 amONT - ORD
1 stop6h 17mFrontier
Deal found 12/10$278
This CheapOair deal was found by Cheapflights users on 12/11. 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.
Thu 12/258:21 pmORD - ONT
1 stop23h 09mFrontier
Thu 1/16:00 amONT - ORD
1 stop6h 17mFrontier
Deal found 12/11$279
This CheapOair deal was found by Cheapflights users on 12/10. 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 12/157:00 amORD - ONT
1 stop9h 25mFrontier
Mon 12/226:00 pmONT - ORD
1 stop18h 17mFrontier
Deal found 12/10$285
This CheapOair deal was found by Cheapflights users on 12/9. 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.
Sun 12/2110:49 pmORD - ONT
1 stop24h 28mFrontier
Mon 12/296:00 pmONT - ORD
1 stop18h 17mFrontier
Deal found 12/9$289
This CheapOair deal was found by Cheapflights users on 12/9. 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.
Sun 12/143:47 pmORD - ONT
1 stop26h 46mFrontier
Sat 12/205:16 pmONT - ORD
1 stop26h 23mFrontier
Deal found 12/9$293
This Booking.com deal was found by Cheapflights users on 12/9. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/1412:59 pmORD - ONT
1 stop27h 05mFrontier
Sun 12/216:00 amONT - ORD
1 stop13h 39mFrontier
Deal found 12/9$294
This Expedia deal was found by Cheapflights users on 12/10. 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.
Thu 12/258:21 pmORD - ONT
1 stop23h 09mFrontier
Wed 12/316:45 amONT - ORD
1 stop15h 27mFrontier
Deal found 12/10$298
This CheapOair deal was found by Cheapflights users on 12/9. 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.
Wed 12/249:34 pmORD - ONT
1 stop13h 19mFrontier
Wed 12/316:45 amONT - ORD
1 stop15h 27mFrontier
Deal found 12/9$299
This Mytrip deal was found by Cheapflights users on 12/10. 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.
Wed 12/319:34 pmORD - ONT
1 stop13h 19mFrontier
Sat 1/36:45 amONT - ORD
1 stop15h 27mFrontier
Deal found 12/10$302

Find flight deals from Chicago to Ontario

Discover tips and strategies to find the most affordable flight options for your journey from Chicago (CHI) 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 December 12, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$148
(Priceline)

One-way from

$52
(Trip.com)

Popular in

November

Cheapest in

October

Average price

$514

Good round-trip deal

$511 or less

Good one-way deal

$299 or less
Provider with most accurate pricing for Chicago (CHI)-Ontario flight deals.
Search Deals
Provider most trusted by Cheapflights users for Chicago (CHI)-Ontario flights.
Search Deals
From Chicago (CHI) to Ontario
Search Deals
One-way flight from Chicago (CHI) to Ontario
Search Deals
Highest demand for flights based on searches. 18% potential increase in price ($79 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($18 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
Search Deals
Price to beat on a round-trip flight from Chicago (CHI) to Ontario.
Search Deals
Price to beat on a one-way flight from Chicago (CHI) to Ontario.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Chicago 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 December 12, 2025.
Use the filters below to find and compare flights from Chicago to Ontario that are best for you.

Fly from

Chicago

Fly to

Ontario

Route

Depart

Return

Price

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Thu 1/8

7:30 am-1:56 pm

1 stop8h 26m

Ontario

Thu 1/15

7:30 am-9:52 pm

2 stops12h 22m

$290

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Fri 1/23

2:20 pm-11:58 pm

2 stops11h 38m

Ontario

Mon 1/26

7:30 am-9:43 pm

2 stops12h 13m

$296

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 1/24

3:35 pm-10:59 am

1 stop21h 24m

Ontario

Mon 1/26

6:00 am-11:50 pm

1 stop15h 50m

$304

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 1/17

8:00 am-8:36 pm

1 stop14h 36m

Ontario

Sun 1/25

6:00 am-5:10 pm

1 stop9h 10m

$304

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Mon 1/26

8:00 am-11:56 pm

1 stop17h 56m

Ontario

Sun 2/1

6:00 am-11:50 pm

1 stop15h 50m

$304

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 1/7

8:00 am-5:03 pm

2 stops11h 03m

Ontario

Sat 1/17

11:53 am-11:50 pm

1 stop9h 57m

$310

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Thu 1/8

2:06 pm-8:10 pm

1 stop8h 04m

Ontario

Sat 1/17

11:53 am-11:50 pm

1 stop9h 57m

$332

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 1/7

7:30 am-1:56 pm

1 stop8h 26m

Ontario

Tue 1/13

1:11 pm-9:52 pm

1 stop6h 41m

$333

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 1/7

7:30 am-1:56 pm

1 stop8h 26m

Ontario

Wed 1/14

6:00 am-1:38 pm

1 stop5h 38m

$333

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sun 2/8

8:00 am-11:56 pm

1 stop17h 56m

Ontario

Tue 2/10

11:53 am-5:10 pm

1 stop27h 17m

$334

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/11

Showing 1-10 of 39 results
1
2
3
4

Compare providers for flights from Chicago to Ontario

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 Chicago to Ontario in December.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice Accuracy3 starsTrust Score*3 stars
JustAirTicketPrice 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 Chicago-Ontario flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Chicago-Ontario flight deals on Cheapflights vs. eDreams >95% of the time. Price accuracy is based on data collected from Chicago-Ontario flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Chicago-Ontario flights, Cheapflights users trust eDreams the most. eDreams 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 Chicago-Ontario 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 Chicago to Ontario

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

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

Use this chart to determine the optimal time to book a round-trip flight from Chicago to Ontario. Price data was last updated on December 5, 2025.

Booking 9 days in advance of your planned departure date is, on average, the best time to get cheap flights from Chicago 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 Chicago to Ontario?

Currently, September is the cheapest month in which you can book a flight from Chicago to Ontario (average of $80). Flying from Chicago to Ontario in January is currently the most expensive (average of $120). 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 CHI to ONT?

Find hourly flight availability from Chicago 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 December 12, 2025.

Unlike in the morning, when flights are generally more expensive, you can save up to 8% on flights from Chicago to Ontario by exploring options for tickets at noon.

What is the cheapest day to fly from Chicago to Ontario?

Use this chart to determine the cheapest time to fly round-trip from Chicago to Ontario. Price data was last updated on September 28, 2025.

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

Weekly flight availability from Chicago to Ontario

Explore weekly flight availability from Chicago 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 December 12, 2025.

The most flights from CHI to ONT are scheduled on a Monday (2 on average). You will have fewer flight options on Friday, which is when the least amount of flights are scheduled (1 on average).

The best insider tips for Chicago to Ontario 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 Chicago to Ontario trip
Airports
MDW

Use the Orange Line train for a quick, affordable trip to MDW, taking less than 30 minutes from downtown Chicago.

Read more about MDWBy Ramsey Qubein
ONT

Consider renting a car at ONT for easy access to Southern California destinations like Palm Springs and Big Bear.

Read more about ONTBy Bill Fink
Our travel experts
Ramsey Qubein

Ramsey Qubein

Expert on MDW

Ramsey Qubein

Ramsey Qubein

An avid traveler and aviation expert who has visited 173 countries, all 50 states and seven continents, Ramsey Qubein flies nearly 400,000 miles a year. As a North Carolina-based freelance journalist for publications including Conde Nast Traveler, Forbes, USA Today and Bloomberg among others, he explores the latest trends in aviation, hospitality, cruises and business.

Read more
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

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 December 12, 2025.
Read through reviews of airlines operating flights from Chicago to Ontario, such as Southwest, United Airlines, and American Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
7.9
Good
4,253 reviews

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
7.9
Good
4,253 reviews
Southwest
7.9
Good
4,253 reviews

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
9,095 reviews
Southwest
7.9
Good
4,253 reviews

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
11,050 reviews
Southwest
7.9
Good
4,253 reviews

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Spirit Airlines
6.3
Okay
8,179 reviews
Southwest
7.9
Good
4,253 reviews

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Frontier
5.8
Fair
3,084 reviews
Southwest
7.9
Good
4,253 reviews

Food

7.0

Comfort

8.0

Crew

8.6

Entertainment

7.5

Overall

7.9

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from Chicago 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 Chicago?

    Ontario (ONT) is the airport you will fly into if you book a flight from Chicago to Ontario. You should not have trouble finding flights to Ontario from Chicago; the airport handles an average of 1 inbound flight from Chicago per day. You should also have plenty of airline options to choose from since 5 airlines have flights to the Ontario airport from Chicago. It is only a 3.1 mi journey from Ontario (ONT) to Ontario’s city center.

  • How long is the flight from Chicago to Ontario?

    A quick flight from Chicago to Ontario can take about 8h 26m. Delta provides one of the quickest options available for as low as $290. There are 1695 mi between Chicago and Ontario. Both multi-stop and nonstop flights can be found to your destination and back.

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

    Flying on Frontier is currently your cheapest option to Ontario, with prices starting at $125. Additional round-trip tickets that might be worth considering are offered by American Airlines and United Airlines, with the lowest prices starting at $231 and $237, respectively. Frontier is currently priced 64% below the average price you’ll pay for this route.

  • What are the cheapest airlines to fly from Chicago 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 $79. United Airlines flights start at $113 while deals on Southwest start at $123 one-way.

  • What are the cheapest flights from Chicago to Ontario?

    While on average a flight from Chicago to Ontario is generally $450, our data shows the cheapest flight currently is $207. When looking at the most popular route, (Chicago O'Hare Intl - Ontario), you can expect to pay $149 for that flight.

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

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

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

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

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

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

    Currently, September is the cheapest month in which you can book a flight from Chicago to Ontario (average of $80). Flying from Chicago to Ontario in January is currently the most expensive (average of $120). 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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Alternative routes for Chicago to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Chicago to Ontario

Discover the top 5 airlines that operate flights from Chicago 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 December 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$125Average$232FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$231Average$452FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$237Average$435FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$246Average$426FlexibilityNo cancel feeOn-time63%
DeltaCheapest$256Average$256FlexibilityNo cancel feeOn-timeN/A

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