HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Chicago

$112+ 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 7/7. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — CHI
jun. 17 — jun. 241
mar. 6/17
mar. 6/24
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

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

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheapflights Tip: The best prices from Ontario to Chicago are usually found in November or September, booked 79 days in advance, depart on a Tuesday or Friday and return on a Tuesday

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 junio 12, 2025.

Round-trip from

$244
(FlightHub)

One-way from

$112
(Trip.com)

Popular in

March

Cheapest in

November

Average price

$322

Good round-trip deal

$344 or less

Good one-way deal

$179 or less
From Ontario to Chicago (CHI)
Search Deals
One-way flight from Ontario to Chicago (CHI)
Search Deals
Highest demand for flights based on searches. 12% potential increase in price ($47 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($11 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2025
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

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 junio 12, 2025.

This FlightHub deal was found by Cheapflights users on 6/10. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 8/229:59 amONT - MDW
1 stop9h 49mFrontier
lun. 8/256:31 pmMDW - ONT
1 stop7h 19mFrontier
Deal found 6/10$244
This FlightHub deal was found by Cheapflights users on 6/10. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 8/2112:59 amONT - ORD
1 stop7h 38mFrontier
lun. 8/2512:31 pmORD - ONT
1 stop8h 03mFrontier
Deal found 6/10$244
This Alaska Airlines deal was found by Cheapflights users on 6/11. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 8/134:00 pmONT - ORD
1 stop11h 40mAlaska Airlines
sáb. 8/166:00 amORD - ONT
1 stop10h 46mAlaska Airlines
Deal found 6/11$283
This American Airlines deal was found by Cheapflights users on 6/11. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 7/316:15 amONT - ORD
1 stop5h 48mAmerican Airlines
jue. 7/315:08 pmORD - ONT
1 stop7h 02mAmerican Airlines
Deal found 6/11$295
This Delta deal was found by Cheapflights users on 6/10. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 10/1412:00 pmONT - MDW
1 stop7h 44mDelta
mar. 10/211:05 pmMDW - ONT
1 stop8h 37mDelta
Deal found 6/10$319
This Hawaiian Airlines deal was found by Cheapflights users on 6/11. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 9/136:00 amONT - ORD
1 stop8h 49mHawaiian Airlines
mié. 9/248:00 amORD - ONT
1 stop8h 09mHawaiian Airlines
Deal found 6/11$323
This Delta deal was found by Cheapflights users on 6/9. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 10/16:45 amONT - ORD
2 stops13h 08mDelta
mar. 10/78:55 amORD - ONT
2 stops12h 47mDelta
Deal found 6/9$329
This Southwest deal was found by Cheapflights users on 6/12. 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.
mar. 8/1911:55 amONT - MDW
Nonstop3h 50mSouthwest
mar. 8/265:25 pmMDW - ONT
Nonstop4h 10mSouthwest
Deal found 6/12$397
This United Airlines deal was found by Cheapflights users on 6/11. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 10/27:02 amONT - ORD
Nonstop4h 03mUnited Airlines
lun. 10/67:59 pmORD - ONT
Nonstop4h 31mUnited Airlines
Deal found 6/11$397

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 junio 12, 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 - MDW

ONTMDW

Ontario

vie. 8/22

9:59 am-9:48 pm

1 stop9h 49m

Chicago Midway

lun. 8/25

6:31 pm-11:50 pm

1 stop7h 19m

$244

OntarioChicago

ONT - ORD

ONTORD

Ontario

jue. 8/21

12:59 am-10:37 am

1 stop7h 38m

Chicago O'Hare Intl

lun. 8/25

12:31 pm-6:34 pm

1 stop8h 03m

$244

OntarioChicago

ONT - ORD

ONTORD

Ontario

mié. 8/13

4:00 pm-5:40 am

1 stop11h 40m

Chicago O'Hare Intl

sáb. 8/16

6:00 am-2:46 pm

1 stop10h 46m

$283

OntarioChicago

ONT - ORD

ONTORD

Ontario

jue. 7/31

6:15 am-2:03 pm

1 stop5h 48m

Chicago O'Hare Intl

jue. 7/31

5:08 pm-10:10 pm

1 stop7h 02m

$295

OntarioChicago

ONT - MDW

ONTMDW

Ontario

mar. 10/14

12:00 pm-9:44 pm

1 stop7h 44m

Chicago Midway

mar. 10/21

1:05 pm-7:42 pm

1 stop8h 37m

$319

OntarioChicago

ONT - ORD

ONTORD

Ontario

sáb. 9/13

6:00 am-4:49 pm

1 stop8h 49m

Chicago O'Hare Intl

mié. 9/24

8:00 am-2:09 pm

1 stop8h 09m

$323

OntarioChicago

ONT - ORD

ONTORD

Ontario

mar. 9/30

10:59 pm-8:34 am

1 stop7h 35m

Chicago O'Hare Intl

sáb. 10/4

10:35 am-7:42 pm

2 stops11h 07m

$342

OntarioChicago

ONT - ORD

ONTORD

Ontario

jue. 8/28

12:59 am-10:37 am

1 stop7h 38m

Chicago O'Hare Intl

mar. 9/2

6:20 am-2:09 pm

1 stop9h 49m

$389

OntarioChicago

ONT - ORD

ONTORD

Ontario

jue. 10/2

7:02 am-1:05 pm

Nonstop4h 03m

Chicago O'Hare Intl

lun. 10/6

7:59 pm-10:30 pm

Nonstop4h 31m

$397

OntarioChicago

ONT - MDW

ONTMDW

Ontario

sáb. 7/19

6:00 am-11:50 am

Nonstop3h 50m

Chicago Midway

mar. 7/29

2:50 pm-8:00 pm

1 stop7h 10m

$407

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/12

Showing 1-10 of 22 results
1
2
3

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

For business travelers, ONT offers a smooth security process, often quicker than LAX, making it ideal for weekday commutes.

Read more about ONTby Bill Fink
MDW

Use the Orange Line train for a quick, budget-friendly trip from MDW to downtown Chicago in under 30 minutes.

Read more about MDWby Ramsey Qubein
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

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 June 9, 2025.

The best time to book flights from Ontario to Chicago is 79 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 $321). 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 junio 12, 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 June 8, 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 junio 12, 2025.
To help decide which airline to fly from Ontario to Chicago, see what other customers have to say about Alaska Airlines, Southwest and Delta. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Crew

8.5

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

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Crew

8.5

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
4,287 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Crew

8.5

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
7,950 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.9
Good
2,494 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Crew

8.5

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
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Overall

8.0

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Crew

8.5

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 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 6 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 $244. Other airlines that can offer you cheap pricing are Alaska Airlines, from $283, and American Airlines, from $295. 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 ($128), Alaska Airlines ($137), and Delta ($138).

  • 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 $924 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 $278.

  • 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 $321). 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
Lansing
Benton Harbor
Porter
Hammond
Valparaiso
Chesterton

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Ontario to Chicago

See prices for flight routes from nearby airports that may be better suited for you.
Los Angeles to O'Hare Intl flights
San Francisco to O'Hare Intl flights
Ontario to O'Hare Intl flights
Santa Ana to O'Hare Intl flights
San Francisco to Midway flights
Burbank to O'Hare Intl flights
San Diego to O'Hare Intl flights
San Jose to O'Hare Intl flights
Oakland to O'Hare Intl flights
Los Angeles to Midway flights
Los Angeles to St. Louis flights
Sacramento to O'Hare Intl flights
Las Vegas to O'Hare Intl flights
Ontario to Midway flights
San Francisco to St. Louis flights
Ontario to St. Louis flights
San Diego to Midway flights
Santa Ana to Midway flights
Oakland to Midway flights
San Jose to Midway flights
Long Beach to O'Hare Intl flights
Sacramento to Midway flights
Las Vegas to Midway flights
Palm Springs to O'Hare Intl flights
Fresno to O'Hare Intl flights
Burbank to St. Louis flights
Reno to O'Hare Intl flights
Burbank to Midway flights
Las Vegas to St. Louis flights
San Diego to St. Louis flights
Sacramento to St. Louis flights
Santa Ana to St. Louis flights
Long Beach to St. Louis flights
Long Beach to Midway flights
Palm Springs to Midway flights
Oakland to St. Louis flights
San Jose to St. Louis flights
Santa Barbara to O'Hare Intl flights
Fresno to Midway flights
Santa Rosa to O'Hare Intl flights
Reno to Midway flights
Ontario to Peoria flights
San Luis Obispo to O'Hare Intl flights
Los Angeles to Evansville flights
Monterey to O'Hare Intl flights
San Diego to Moline flights
Medford to O'Hare Intl flights
San Diego to Peoria flights
Santa Ana to Moline flights
Los Angeles to Moline flights

Top 6 airlines flying from Ontario to Chicago

Discover the top 6 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 junio 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$99Average$217FlexibilityNo cancel feeOn-time65%
FrontierCheapest$108Average$179FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$227Average$355FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$237Average$441FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$238Average$386FlexibilityNo cancel feeOn-time71%
DeltaCheapest$241Average$400FlexibilityNo cancel feeOn-timeN/A

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.