HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Chicago

$67+ 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 2/25. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — CHI
feb. 28 — mar. 71
sáb. 2/28
sáb. 3/7
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 June or September, booked 69 days in advance, depart on a Thursday or Wednesday and return on a Sunday

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 enero 29, 2026.

This Kiwi.com deal was found by Cheapflights users on 1/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 2/288:21 am
ONT
-
ORD
1 stop12h 56m
Frontier
sáb. 3/75:30 am
ORD
-
ONT
2 stops20h 29m
Frontier
Deal found 1/27$158
This CheapOair deal was found by Cheapflights users on 1/28. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 2/218:21 am
ONT
-
ORD
1 stop12h 56m
Frontier
lun. 2/237:19 pm
ORD
-
ONT
1 stop20h 33m
Frontier
Deal found 1/28$169
This Kiwi.com deal was found by Cheapflights users on 1/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 3/38:40 am
ONT
-
ORD
2 stops24h 11m
Frontier
jue. 3/54:16 pm
ORD
-
ONT
1 stop9h 43m
Frontier
Deal found 1/28$170
This Kiwi.com deal was found by Cheapflights users on 1/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 3/242:23 pm
ONT
-
ORD
1 stop13h 45m
Frontier
mié. 4/15:15 pm
ORD
-
ONT
1 stop27h 30m
Frontier
Deal found 1/27$172
This Mytrip deal was found by Cheapflights users on 1/27. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 2/262:08 pm
ONT
-
ORD
1 stop7h 06m
Frontier
lun. 3/27:19 pm
ORD
-
ONT
1 stop19h 52m
Frontier
Deal found 1/27$174
This Frontier deal was found by Cheapflights users on 1/27. 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.
mar. 4/147:29 pm
ONT
-
ORD
1 stop9h 18m
Frontier
sáb. 4/184:55 pm
ORD
-
ONT
1 stop7h 47m
Frontier
Deal found 1/27$180
This Kiwi.com deal was found by Cheapflights users on 1/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 3/57:22 pm
ONT
-
ORD
1 stop8h 46m
Frontier
mié. 3/114:28 pm
ORD
-
ONT
2 stops22h 43m
Frontier
Deal found 1/28$188
This CheapOair deal was found by Cheapflights users on 1/26. 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.
mié. 4/86:20 am
ONT
-
ORD
1 stop5h 59m
Frontier
jue. 4/1610:55 am
ORD
-
ONT
1 stop15h 00m
Frontier
Deal found 1/26$191
This Frontier deal was found by Cheapflights users on 1/27. 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.
jue. 2/262:08 pm
ONT
-
ORD
1 stop7h 06m
Frontier
jue. 3/54:16 pm
ORD
-
ONT
1 stop9h 43m
Frontier
Deal found 1/27$193
This CheapOair deal was found by Cheapflights users on 1/27. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 2/197:22 pm
ONT
-
ORD
1 stop20h 04m
Frontier
lun. 2/237:19 pm
ORD
-
ONT
1 stop20h 33m
Frontier
Deal found 1/27$195
This Kiwi.com deal was found by Cheapflights users on 1/27. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 2/218:21 am
ONT
-
ORD
1 stop12h 56m
Frontier
mar. 2/246:02 pm
ORD
-
ONT
2 stops29h 32m
Frontier
Deal found 1/27$199
This Kiwi.com deal was found by Cheapflights users on 1/28. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 2/192:06 pm
ONT
-
MDW
1 stop21h 47m
Frontier
lun. 2/237:25 pm
MDW
-
ONT
2 stops28h 09m
Frontier
Deal found 1/28$200

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 enero 29, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$158
(Kiwi.com)

One-way from

$67
(Kiwi.com)

Popular in

December

Cheapest in

June

Average price

$507

Good round-trip deal

$372 or less

Good one-way deal

$153 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. 18% potential increase in price ($86 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($14 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 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 enero 29, 2026.
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

mié. 3/4

4:02 pm-12:01 pm

1 stop17h 59m

Chicago O'Hare Intl

lun. 3/9

7:00 am-11:52 pm

2 stops18h 52m

$305

OntarioChicago

ONT - MDW

ONTMDW

Ontario

mié. 2/25

1:15 pm-10:31 pm

1 stop7h 16m

Chicago Midway

mié. 3/4

6:00 am-12:02 pm

1 stop8h 02m

$307

OntarioChicago

ONT - ORD

ONTORD

Ontario

mar. 3/31

11:59 am-12:40 am

1 stop10h 41m

Chicago O'Hare Intl

sáb. 4/4

5:00 pm-10:48 pm

1 stop7h 48m

$307

OntarioChicago

ONT - MDW

ONTMDW

Ontario

sáb. 2/21

10:20 pm-9:54 am

1 stop9h 34m

Chicago Midway

mar. 2/24

1:49 pm-11:49 pm

2 stops12h 00m

$312

OntarioChicago

ONT - ORD

ONTORD

Ontario

jue. 3/5

12:02 pm-11:56 pm

1 stop9h 54m

Chicago O'Hare Intl

lun. 3/9

5:29 pm-11:32 pm

1 stop8h 03m

$335

OntarioChicago

ONT - ORD

ONTORD

Ontario

vie. 2/27

7:37 pm-2:11 pm

2 stops16h 34m

Chicago O'Hare Intl

sáb. 2/28

3:54 pm-11:32 pm

1 stop9h 38m

$344

OntarioChicago

ONT - ORD

ONTORD

Ontario

mar. 3/31

11:59 am-12:40 am

1 stop10h 41m

Chicago O'Hare Intl

lun. 4/6

7:10 pm-11:51 pm

1 stop6h 41m

$346

OntarioChicago

ONT - MDW

ONTMDW

Ontario

sáb. 3/14

10:25 pm-9:56 am

1 stop9h 31m

Chicago Midway

lun. 3/16

1:10 pm-11:51 pm

2 stops12h 41m

$351

OntarioChicago

ONT - MDW

ONTMDW

Ontario

vie. 3/13

10:25 pm-9:56 am

1 stop9h 31m

Chicago Midway

mié. 3/18

9:35 am-9:00 pm

2 stops13h 25m

$351

OntarioChicago

ONT - ORD

ONTORD

Ontario

vie. 3/13

10:25 pm-8:30 am

1 stop8h 05m

Chicago O'Hare Intl

mié. 3/18

7:20 am-12:23 pm

1 stop7h 03m

$356

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/27

Showing 1-10 of 49 results
1
2
3
...
5

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 January.
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

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 January 23, 2026.

The best time to book flights from Ontario to Chicago is 68 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, March is the cheapest month in which you can book a flight from Ontario to Chicago (average of $77). Flying from Ontario to Chicago in October is currently the most expensive (average of $147). 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 enero 29, 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.

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

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 enero 29, 2026.
See what other customers who have flown with Southwest, Delta, and United 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
8.0
Very good
4,267 reviews

Comfort

8.0

Crew

8.6

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
Southwest
8.0
Very good
4,267 reviews
Southwest
8.0
Very good
4,267 reviews

Comfort

8.0

Crew

8.6

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
Delta
7.9
Good
8,128 reviews
Southwest
8.0
Very good
4,267 reviews

Comfort

8.0

Crew

8.6

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
United Airlines
7.4
Good
9,215 reviews
Southwest
8.0
Very good
4,267 reviews

Comfort

8.0

Crew

8.6

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
American Airlines
7.2
Good
11,205 reviews
Southwest
8.0
Very good
4,267 reviews

Comfort

8.0

Crew

8.6

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.
Frontier
5.7
Fair
3,056 reviews
Southwest
8.0
Very good
4,267 reviews

Comfort

8.0

Crew

8.6

Food

7.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

William Drew,Nov 2025

SJC - HNL

Flight crew was amazing! Usually they're very good on Southwest, but this crew went above and beyond. I have never ever seen so many rounds of drink service on a flight before.

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 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?

    Alaska Airlines and Delta can get you from Ontario to Chicago in just under 7h 16m. Your travel time can differ by up to 10h 43m. 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 $102. Other airlines that can offer you cheap pricing are United Airlines, from $226, and Southwest, from $237. 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), Southwest ($113), and United Airlines ($113).

  • 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 $627 for a flight from Ontario to Chicago. The cheapest flight overall is $101 while the most popular route, (Ontario - Chicago O'Hare Intl) is currently priced at $180.

  • 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, March is the cheapest month in which you can book a flight from Ontario to Chicago (average of $77). Flying from Ontario to Chicago in October is currently the most expensive (average of $147). 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
Lansing
Merrillville
Hammond
Porter
Benton Harbor

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
Los Angeles to Midway flights
Ontario to O'Hare Intl flights
Santa Ana to O'Hare Intl flights
San Diego to O'Hare Intl flights
San Francisco to Midway flights
Sacramento to O'Hare Intl flights
San Jose to O'Hare Intl flights
Las Vegas to O'Hare Intl flights
Los Angeles to St. Louis flights
Burbank to O'Hare Intl flights
Oakland to O'Hare Intl flights
San Francisco to St. Louis flights
Sacramento to Midway flights
San Diego to Midway flights
Santa Ana to Midway flights
San Jose to Midway flights
San Diego to St. Louis flights
Las Vegas to Midway flights
Ontario to Midway flights
Fresno to O'Hare Intl flights
Oakland to Midway flights
Ontario to St. Louis flights
Las Vegas to St. Louis flights
Reno to O'Hare Intl flights
Burbank to Midway flights
Palm Springs to O'Hare Intl flights
Long Beach to O'Hare Intl flights
Santa Barbara to O'Hare Intl flights
Sacramento to St. Louis flights
Monterey to O'Hare Intl flights
San Jose to St. Louis flights
Santa Ana to St. Louis flights
Fresno to Midway flights
Oakland to St. Louis flights
Burbank to St. Louis flights
San Luis Obispo to O'Hare Intl flights
Los Angeles to Moline flights
Santa Ana to Peoria flights
Reno to Midway flights
Fresno to St. Louis flights
Long Beach to Midway flights
Palm Springs to Midway flights
Los Angeles to Peoria flights
Medford to O'Hare Intl flights
Palm Springs to St. Louis flights
Bakersfield to O'Hare Intl flights
Reno to St. Louis flights
Ontario to Peoria flights

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 enero 29, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$102Average$229FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$226Average$397FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$237Average$399FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$246Average$409FlexibilityNo cancel feeOn-time71%
DeltaCheapest$254Average$354FlexibilityNo 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.