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$102+ 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 4/12. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — CHI
Apr 2 — Apr 91
Wed 4/2
Wed 4/9
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 November or September, booked 88 days in advance, depart on a Tuesday or Wednesday and return on a Thursday

Cheap 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 March 28, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$227
(United Airlines)

One-way from

$102
(Trip.com)

Popular in

March

Cheapest in

November

Average price

$380

Good round-trip deal

$317 or less

Good one-way deal

$158 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.
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From Ontario to Chicago (CHI)
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One-way flight from Ontario to Chicago (CHI)
Search Deals
Highest demand for flights based on searches. 8% potential increase in price ($26 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($6 potential savings vs. average RT price).
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Average for round-trip flights in March 2025
Search Deals
Price to beat on a round-trip flight from Ontario to Chicago (CHI).
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Price to beat on a one-way flight from Ontario to Chicago (CHI).
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Find 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 March 28, 2025.

This United Airlines deal was found by Cheapflights users on 3/27. 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.
Mon 5/267:00 amONT - ORD
Nonstop4h 03mUnited Airlines
Fri 5/307:55 pmORD - ONT
Nonstop4h 31mUnited Airlines
Deal found 3/27$227
This Cheapflightsfares deal was found by Cheapflights users on 3/27. 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.
Fri 4/189:41 pmONT - MDW
1 stop5h 42mFrontier
Tue 4/226:45 amMDW - ONT
1 stop6h 35mFrontier
Deal found 3/27$236
This Frontier deal was found by Cheapflights users on 3/27. 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 4/2512:11 pmONT - ORD
1 stop9h 26mFrontier
Fri 5/25:21 pmORD - ONT
1 stop8h 38mFrontier
Deal found 3/27$238
This Southwest deal was found by Cheapflights users on 3/27. 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 7/196:15 amONT - ORD
1 stop6h 45mSouthwest
Mon 7/215:25 pmORD - ONT
1 stop5h 45mSouthwest
Deal found 3/27$242
This Southwest deal was found by Cheapflights users on 3/27. 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 9/258:35 pmONT - MDW
1 stop6h 35mSouthwest
Mon 9/293:20 pmMDW - ONT
1 stop6h 25mSouthwest
Deal found 3/27$247
This Delta deal was found by Cheapflights users on 3/27. 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 4/267:00 amONT - MDW
1 stop8h 59mDelta
Mon 4/284:59 pmMDW - ONT
1 stop7h 37mDelta
Deal found 3/27$257
This Delta deal was found by Cheapflights users on 3/27. 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 5/35:15 pmONT - ORD
1 stop5h 38mDelta
Wed 5/77:30 amORD - ONT
1 stop6h 45mDelta
Deal found 3/27$257
This Hawaiian Airlines deal was found by Cheapflights users on 3/27. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 4/266:00 amONT - ORD
1 stop9h 00mHawaiian Airlines
Sat 5/39:00 amORD - ONT
1 stop8h 32mHawaiian Airlines
Deal found 3/27$267
This Alaska Airlines deal was found by Cheapflights users on 3/27. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/237:17 pmONT - ORD
1 stop8h 23mAlaska Airlines
Fri 10/35:54 pmORD - ONT
1 stop8h 05mAlaska Airlines
Deal found 3/27$287
This American Airlines deal was found by Cheapflights users on 3/28. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/52:40 pmONT - ORD
1 stop8h 19mAmerican Airlines
Sun 6/85:00 amORD - ONT
1 stop7h 04mAmerican Airlines
Deal found 3/28$312

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 March 28, 2025.
Use the filters below to find and compare flights from Ontario to Chicago that are best for you.

Fly from

Ontario

Fly to

Chicago

Route

Depart

Return

Price

OntarioChicago

ONT - ORD

ONTORD

Ontario

Mon 5/26

7:00 am-1:03 pm

Nonstop4h 03m

Chicago O'Hare Intl

Fri 5/30

7:55 pm-10:26 pm

Nonstop4h 31m

$227

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Fri 4/18

4:25 pm-12:21 am

1 stop5h 56m

Chicago Midway

Tue 4/22

6:45 am-11:20 am

1 stop6h 35m

$236

OntarioChicago

ONT - ORD

ONTORD

Ontario

Fri 4/25

12:11 pm-11:37 pm

1 stop9h 26m

Chicago O'Hare Intl

Fri 5/2

5:21 pm-11:59 pm

1 stop8h 38m

$238

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Tue 4/29

12:00 pm-10:15 pm

1 stop8h 15m

Chicago Midway

Fri 5/9

8:25 am-2:10 pm

1 stop7h 45m

$247

OntarioChicago

ONT - ORD

ONTORD

Ontario

Tue 5/6

7:00 am-3:00 pm

1 stop6h 00m

Chicago O'Hare Intl

Tue 5/13

6:55 pm-11:00 pm

1 stop6h 05m

$247

OntarioChicago

ONT - MDW

ONTMDW

Ontario

Sat 4/26

7:00 am-5:59 pm

1 stop8h 59m

Chicago Midway

Mon 4/28

4:59 pm-10:36 pm

1 stop7h 37m

$257

OntarioChicago

ONT - ORD

ONTORD

Ontario

Sat 5/3

5:15 pm-12:53 am

1 stop5h 38m

Chicago O'Hare Intl

Wed 5/7

7:30 am-12:15 pm

1 stop6h 45m

$257

OntarioChicago

ONT - ORD

ONTORD

Ontario

Sat 4/26

6:00 am-5:00 pm

1 stop9h 00m

Chicago O'Hare Intl

Sat 5/3

9:00 am-3:32 pm

1 stop8h 32m

$267

OntarioChicago

ONT - ORD

ONTORD

Ontario

Wed 4/30

11:46 am-11:59 pm

1 stop10h 13m

Chicago O'Hare Intl

Sat 5/3

9:00 am-3:32 pm

1 stop8h 32m

$287

OntarioChicago

ONT - ORD

ONTORD

Ontario

Thu 6/5

2:40 pm-12:59 am

1 stop8h 19m

Chicago O'Hare Intl

Sun 6/8

5:00 am-10:04 am

1 stop7h 04m

$312

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/28

Showing 1-10 of 20 results
1
2

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 March.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy3 starsTrust Score*3 stars
FlightnetworkPrice Accuracy2 starsTrust Score*3 stars
CheapfaremartPrice Accuracy-Trust 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

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

Use this chart to determine the optimal time to book a round-trip flight from Ontario to Chicago. Price data was last updated on March 21, 2025.

The best time to book flights from Ontario to Chicago is 88 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.

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

Currently, August is the cheapest month in which you can book a flight from Ontario to Chicago (average of $245). Flying from Ontario to Chicago in March is currently the most expensive (average of $323). 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 March 28, 2025.

Unlike at noon, when flights are generally more expensive, you can save up to 54% on flights from Ontario to Chicago by exploring options for tickets in the evening.

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

Use this chart to determine the cheapest time to fly round-trip from Ontario to Chicago. Price data was last updated on March 23, 2025.

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

Rainfall in Chicago by month

Plan your trip to Chicago by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Chicago ranges from 1.7 - 4.9 inches per month. August is typically the wettest month, when rainfall can reach 4.9 in. January is typically the driest time to visit Chicago when rainfall is around 1.7 in.

Temperature in Chicago by month

Plan your trip to Chicago by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Chicago, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 23.0 F).

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 March 28, 2025.
To help decide which airline to fly from Ontario to Chicago, see what other customers have to say about Southwest, Alaska Airlines and Delta. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Crew

8.7

Boarding

8.2

Food

7.1

Comfort

8.1

Overall

8.1

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
8.1
Very good
4,274 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Crew

8.7

Boarding

8.2

Food

7.1

Comfort

8.1

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Alaska Airlines
8.0
Very good
9,797 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Crew

8.7

Boarding

8.2

Food

7.1

Comfort

8.1

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Delta
8.0
Very good
7,897 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Crew

8.7

Boarding

8.2

Food

7.1

Comfort

8.1

Overall

8.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Hawaiian Airlines
7.9
Good
2,336 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Crew

8.7

Boarding

8.2

Food

7.1

Comfort

8.1

Overall

8.1

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
8,603 reviews
Southwest
8.1
Very good
4,274 reviews

Entertainment

7.6

Crew

8.7

Boarding

8.2

Food

7.1

Comfort

8.1

Overall

8.1

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 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 0 outbound flights to Chicago per day. You should also have plenty of airline options to choose from since 7 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.

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

    Cheapflights users have booked flights from Ontario to Chicago round-trip from $227. Other airlines that can offer you cheap pricing are Frontier, from $236, and Southwest, from $242. These flights start at 26% 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 ($102), United Airlines ($114), and Southwest ($119).

  • 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 $669 for a flight from Ontario to Chicago. The cheapest flight overall is $113 while the most popular route, (Ontario - Chicago O'Hare Intl) is currently priced at $227.

  • 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, August is the cheapest month in which you can book a flight from Ontario to Chicago (average of $245). Flying from Ontario to Chicago in March is currently the most expensive (average of $323). 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 Ontario?

Book flights to Ontario if you plan to visit one of these locations
Merrillville
New Buffalo
Hammond
Benton Harbor
Porter
Lansing
Valparaiso
Chesterton

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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 7 airlines flying from Ontario to Chicago

Discover the top 7 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 March 28, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$74Average$197FlexibilityNo cancel feeOn-time65%
FrontierCheapest$108Average$186FlexibilityNo cancel feeOn-time62%
Alaska AirlinesCheapest$161Average$438FlexibilityNo cancel feeOn-time75%
DeltaCheapest$241Average$404FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$246Average$392FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$246Average$372FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$262Average$470FlexibilityNo cancel feeOn-time63%
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