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$108+ Cheap flights from Ontario (ONT) to Chicago (CHI)

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 8/1. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — CHI
Jul 20 — Jul 271
Mon 7/20
Mon 7/27
1 adult, Economy
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Find cheap flights from Ontario to Chicago 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 Ontario to Chicago are usually found in January or October, booked 85 days in advance, depart on a Wednesday or Thursday and return on a Wednesday

Cheap flight deals from Ontario to Chicago

Cheapest flights from Ontario to Chicago
Explore the most affordable flight options available from Ontario to Chicago. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 20, 2026.

This Kiwi.com deal was found by Cheapflights users on 6/16. 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 7/149:32 am
ONT
-
ORD
1 stop13h 17m
Frontier
Tue 7/219:57 pm
ORD
-
ONT
2 stops19h 17m
Frontier
Deal found 6/16$296
This Southwest deal was found by Cheapflights users on 6/15. 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.
Wed 8/2611:55 pm
ONT
-
MDW
Nonstop3h 50m
Southwest
Wed 9/95:25 pm
MDW
-
ONT
Nonstop4h 10m
Southwest
Deal found 6/15$297
This Booking.com deal was found by Cheapflights users on 6/15. 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.
Tue 6/301:33 pm
ONT
-
ORD
1 stop13h 34m
Frontier
Tue 7/145:46 pm
ORD
-
ONT
1 stop15h 46m
Frontier
Deal found 6/15$297
This Southwest deal was found by Cheapflights users on 6/16. 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.
Tue 8/46:50 am
ONT
-
MDW
2 stops8h 20m
Southwest
Thu 8/68:00 am
MDW
-
ONT
2 stops9h 05m
Southwest
Deal found 6/16$298
This Delta deal was found by Cheapflights users on 6/16. 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.
Wed 8/121:06 pm
ONT
-
ORD
1 stop6h 24m
Delta
Mon 8/177:44 pm
ORD
-
ONT
1 stop5h 50m
Delta
Deal found 6/16$298
This Southwest deal was found by Cheapflights users on 6/15. 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.
Tue 8/46:50 am
ONT
-
MDW
2 stops8h 20m
Southwest
Sat 8/86:55 am
MDW
-
ONT
1 stop10h 20m
Southwest
Deal found 6/15$299
This Frontier deal was found by Cheapflights users on 6/16. 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 8/33:40 pm
ONT
-
ORD
1 stop11h 57m
Frontier
Wed 8/57:15 am
ORD
-
ONT
1 stop9h 59m
Frontier
Deal found 6/16$299
This Frontier deal was found by Cheapflights users on 6/15. 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 7/213:40 pm
ONT
-
ORD
1 stop11h 57m
Frontier
Tue 8/259:33 am
ORD
-
ONT
1 stop9h 15m
Frontier
Deal found 6/15$300
This Kiwi.com deal was found by Cheapflights users on 6/15. 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.
Sat 7/43:34 pm
ONT
-
ORD
1 stop11h 33m
Frontier
Wed 7/157:15 am
ORD
-
ONT
1 stop9h 59m
Frontier
Deal found 6/15$302
This Delta deal was found by Cheapflights users on 6/15. 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.
Thu 8/61:06 pm
ONT
-
ORD
1 stop6h 24m
Delta
Tue 8/112:00 pm
ORD
-
ONT
2 stops10h 45m
Delta
Deal found 6/15$303
This Booking.com deal was found by Cheapflights users on 6/16. 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.
Wed 7/291:38 pm
ONT
-
ORD
1 stop13h 59m
Frontier
Sun 8/27:15 am
ORD
-
ONT
1 stop26h 48m
Frontier
Deal found 6/16$304
This CheapOair deal was found by Cheapflights users on 6/18. 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.
Tue 7/79:32 am
ONT
-
ORD
1 stop13h 17m
Frontier
Tue 7/149:57 pm
ORD
-
ONT
1 stop14h 07m
Frontier
Deal found 6/18$305

Find flight deals from Ontario to Chicago

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to Chicago (CHI). 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 20, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$295
(Kiwi.com)

One-way from

$108
(Trip.com)

Popular in

December

Cheapest in

January

Average price

$477

Good round-trip deal

$430 or less

Good one-way deal

$218 or less
Provider with most accurate pricing for Ontario-Chicago (CHI) flight deals.
Search Deals
Provider most trusted by Cheapflights users for Ontario-Chicago (CHI) flights.
Search Deals
From Ontario to Chicago (CHI)
Search Deals
One-way flight from Ontario to Chicago (CHI)
Search Deals
Highest demand for flights based on searches. 2% potential increase in price ($9 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($10 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2026
Search Deals
Price to beat on a round-trip flight from Ontario to Chicago (CHI).
Search Deals
Price to beat on a one-way flight from Ontario to Chicago (CHI).
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to Chicago 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 20, 2026.
Use the filters below to find and compare flights from Ontario to Chicago that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioChicago

ONT - ORD

ONTORD

Ontario

Wed 8/12

6:20 am-9:30 pm

2 stops13h 10m

Chicago O'Hare Intl

Mon 8/17

5:57 pm-11:34 pm

2 stops7h 37m

$308

OntarioChicago

ONT - ORD

ONTORD

Ontario

Thu 8/20

1:06 pm-9:30 pm

1 stop6h 24m

Chicago O'Hare Intl

Mon 8/24

2:00 pm-10:45 pm

2 stops10h 45m

$322
Quickest round-trip

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Wed 9/16

11:55 pm-5:45 am

Nonstop3h 50m

Chicago Midway

Wed 9/23

5:25 pm-7:35 pm

Nonstop4h 10m

$323

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Wed 8/19

7:00 am-4:00 pm

2 stops7h 00m

Chicago Midway

Wed 8/19

5:15 pm-10:05 pm

1 stop6h 50m

$348

OntarioChicago

ONT - ORD

ONTORD

Ontario

Tue 7/14

1:50 pm-12:59 am

1 stop9h 09m

Chicago O'Hare Intl

Thu 7/16

8:18 pm-10:51 pm

Nonstop4h 33m

$349

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Sun 8/9

11:55 pm-5:45 am

Nonstop3h 50m

Chicago Midway

Wed 8/12

4:45 pm-8:55 pm

1 stop6h 10m

$353

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Sat 8/1

3:00 pm-12:20 am

1 stop7h 20m

Chicago Midway

Tue 8/4

6:00 am-12:30 pm

1 stop8h 30m

$363

OntarioChicago

ONT - ORD

ONTORD

Ontario

Wed 9/9

7:00 am-1:10 pm

Nonstop4h 10m

Chicago O'Hare Intl

Sat 9/12

5:30 pm-7:57 pm

Nonstop4h 27m

$368

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Wed 7/8

4:35 pm-12:10 am

1 stop5h 35m

Chicago Midway

Tue 7/14

5:50 pm-10:50 pm

2 stops7h 00m

$368

OntarioChicago

ONT - ORD

ONTORD

Ontario

Tue 10/6

9:55 am-5:57 pm

1 stop6h 02m

Chicago O'Hare Intl

Mon 10/12

7:30 am-12:30 pm

1 stop7h 00m

$373

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/15

Showing 1-10 of 57 resultsSorted by cheapest first
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2
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6

Compare providers for flights from Ontario to Chicago

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 Chicago in June.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
Justfly.comPrice Accuracy3 starsTrust Score*3 stars
MytripPrice Accuracy2 starsTrust Score*3 stars

*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-Chicago flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-Chicago flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-Chicago flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Ontario-Chicago 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-Chicago 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 Chicago

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

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

Currently, September is the cheapest month in which you can book a flight from Ontario to Chicago (average of $102). Flying from Ontario to Chicago in June is currently the most expensive (average of $230). 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 CHI?

Find hourly flight availability from Ontario to Chicago. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 20, 2026.

When flying from Ontario to Chicago, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Weekly flight availability from Ontario to Chicago

Explore weekly flight availability from Ontario to Chicago. 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 20, 2026.

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

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

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

The best time to book flights from Ontario to Chicago is 74 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

The best insider tips for Ontario to Chicago 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 Chicago trip
Our travel experts
Ramsey Qubein

Ramsey Qubein

Expert on MDW

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 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 Chicago

Get insights into the airlines that provide service to Chicago. 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 Chicago. Reviews last updated June 20, 2026.
See what other customers who have flown with Southwest,Delta, andUnited Airlines from Ontario to Chicago have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
7.9
Good
4,242 reviews

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

7.9

Food

7.0

Crew

8.6

Reviews

1 / 20
6.0
Good

Reza,Jun 2026

TPA - MDW

The seats were super cramped and couldn’t move without hitting other passengers
Southwest
7.9
Good
4,242 reviews
Southwest
7.9
Good
4,242 reviews

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

7.9

Food

7.0

Crew

8.6

Reviews

1 / 20
6.0
Good

Reza,Jun 2026

TPA - MDW

The seats were super cramped and couldn’t move without hitting other passengers
Delta
7.8
Good
8,421 reviews
Southwest
7.9
Good
4,242 reviews

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

7.9

Food

7.0

Crew

8.6

Reviews

1 / 20
6.0
Good

Reza,Jun 2026

TPA - MDW

The seats were super cramped and couldn’t move without hitting other passengers
United Airlines
7.4
Good
9,863 reviews
Southwest
7.9
Good
4,242 reviews

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

7.9

Food

7.0

Crew

8.6

Reviews

1 / 20
6.0
Good

Reza,Jun 2026

TPA - MDW

The seats were super cramped and couldn’t move without hitting other passengers
Frontier
5.6
Fair
2,877 reviews
Southwest
7.9
Good
4,242 reviews

Entertainment

7.5

Boarding

8.1

Comfort

8.0

Overall

7.9

Food

7.0

Crew

8.6

Reviews

1 / 20
6.0
Good

Reza,Jun 2026

TPA - MDW

The seats were super cramped and couldn’t move without hitting other passengers

Related info for your journey

Find useful and relevant information for your journey from Ontario to Chicago. 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 from for flights from Ontario to Chicago?

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

  • How long is the flight from Ontario to Chicago?

    Delta, Southwest, and United Airlines can get you from Ontario to Chicago in just under 3h 50m. Your travel time can differ by up to 9h 20m. The distance from Ontario to Chicago is about 1701 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

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

    Cheapflights users have booked flights from Ontario to Chicago round-trip from $117. Other airlines that can offer you cheap pricing are United Airlines, from $255, and Southwest, from $258. These flights start at 73% lower than the current average price 3 months from now.

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

    The cheapest airlines for a one-way flight from Ontario to Chicago are Frontier ($82), American Airlines ($118), and Delta ($118).

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

    Most travelers choose Ontario - Chicago O'Hare Intl, Ontario - Chicago Midway or Ontario - Chicago Greater Rockford when deciding on the best route from Ontario to Chicago.

  • What are the cheapest flights from Ontario to Chicago?

    On average you can expect to pay $775 for a flight from Ontario to Chicago. The cheapest flight overall is $163 while the most popular route, (Ontario - Chicago O'Hare Intl) is currently priced at $239.

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

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

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

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

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

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

    Currently, September is the cheapest month in which you can book a flight from Ontario to Chicago (average of $102). Flying from Ontario to Chicago in June is currently the most expensive (average of $230). 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 Chicago?

Book flights to Chicago if you plan to visit one of these locations
Benton Harbor
Lansing
Merrillville
Hammond
Porter

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Alternative routes for Ontario to Chicago

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

Discover the top 5 airlines that operate flights from Ontario to Chicago. 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 20, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$117Average$280FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$255Average$462FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$258Average$425FlexibilityNo cancel feeOn-time63%
DeltaCheapest$260Average$446FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$316Average$492FlexibilityNo cancel feeOn-time71%

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