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Ontario

$72+ 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 9/10. Fares are subject to change and may not be available on all flights or dates of travel.
CHI — ONT
Sep 11 — Sep 181
Fri 9/11
Fri 9/18
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”

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Cheapflights Tip: The best prices from Chicago to Ontario are usually found in October or August, booked 51 days in advance, depart on a Wednesday or Thursday and return on a Tuesday

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 August 12, 2026.

This Expedia deal was found by Cheapflights users on 8/12. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/101:01 pm -
1 stop7h 38m
Mon 9/148:24 pm -
1 stop7h 14m
Deal found 8/12$146
This Booking.com deal was found by Cheapflights users on 8/12. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/146:30 am -
1 stop6h 00m
Sat 9/2610:04 am -
1 stop17h 34m
Deal found 8/12$152
This CheapOair deal was found by Cheapflights users on 8/12. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/711:06 am -
1 stop14h 49m
Mon 11/911:19 am -
1 stop16h 16m
Deal found 8/12$156
This Frontier deal was found by Cheapflights users on 8/11. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/18:45 am -
1 stop12h 16m
Fri 9/49:33 am -
1 stop13h 16m
Deal found 8/11$162
This Frontier deal was found by Cheapflights users on 8/12. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/39:26 pm -
1 stop13h 12m
Sun 9/68:17 am -
1 stop10h 14m
Deal found 8/12$162
This Frontier deal was found by Cheapflights users on 8/11. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/111:01 pm -
1 stop7h 38m
Mon 9/148:24 pm -
1 stop7h 14m
Deal found 8/11$164
This Southwest deal was found by Cheapflights users on 8/11. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/102:00 pm -
Nonstop4h 10m
Mon 9/1411:55 pm -
Nonstop3h 50m
Deal found 8/11$165
This United Airlines deal was found by Cheapflights users on 8/11. 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.
Thu 9/108:33 pm -
Nonstop4h 26m
Sat 9/197:00 am -
Nonstop4h 10m
Deal found 8/11$167
This Gotogate deal was found by Cheapflights users on 8/11. 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 Gotogate is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/28:55 pm -
1 stop21h 39m
Mon 10/58:24 pm -
1 stop7h 14m
Deal found 8/11$168
This CheapOair deal was found by Cheapflights users on 8/12. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/292:41 pm -
1 stop21h 23m
Thu 9/33:40 pm -
1 stop25h 22m
Deal found 8/12$172
This Trip.com deal was found by Cheapflights users on 8/11. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/248:11 pm -
1 stop21h 43m
Tue 9/87:56 pm -
1 stop26h 27m
Deal found 8/11$173
This Booking.com deal was found by Cheapflights users on 8/11. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/238:11 pm -
1 stop22h 11m
Tue 9/87:56 pm -
1 stop26h 27m
Deal found 8/11$174

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 August 12, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$146
(Frontier)

One-way from

$72
(United Airlines)

Popular in

January

Cheapest in

October

Average price

$301

Good round-trip deal

$301 or less

Good one-way deal

$206 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. 14% potential increase in price ($70 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 August 2026
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 August 12, 2026.
Use the filters below to find and compare flights from Chicago to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Thu 9/10

8:33 pm-10:59 pm

Nonstop4h 26m

Ontario

Sat 9/19

7:00 am-1:10 pm

Nonstop4h 10m

$167

ChicagoOntario

MDW Chicago Midway - ONT Ontario

MDWONT

Chicago Midway

Fri 9/25

2:00 pm-4:10 pm

Nonstop4h 10m

Ontario

Mon 9/28

11:55 pm-5:45 am

Nonstop3h 50m

$188

ChicagoOntario

MDW Chicago Midway - ONT Ontario

MDWONT

Chicago Midway

Fri 10/16

11:55 am-2:10 pm

Nonstop4h 15m

Ontario

Mon 10/19

11:55 pm-5:40 am

Nonstop3h 45m

$189

ChicagoOntario

MDW Chicago Midway - ONT Ontario

MDWONT

Chicago Midway

Fri 10/23

3:45 pm-10:15 pm

2 stops8h 30m

Ontario

Tue 10/27

11:55 pm-5:40 am

Nonstop3h 45m

$205
Quickest round-trip

ChicagoOntario

MDW Chicago Midway - ONT Ontario

MDWONT

Chicago Midway

Fri 9/25

2:00 pm-4:10 pm

Nonstop4h 10m

Ontario

Fri 10/2

11:55 pm-5:40 am

Nonstop3h 45m

$211

ChicagoOntario

MDW Chicago Midway - ONT Ontario

MDWONT

Chicago Midway

Fri 9/11

2:00 pm-4:10 pm

Nonstop4h 10m

Ontario

Fri 9/18

12:50 pm-11:25 pm

2 stops8h 35m

$220

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Thu 10/29

4:15 pm-6:47 pm

Nonstop4h 32m

Ontario

Mon 11/2

1:35 pm-12:59 am

1 stop9h 24m

$235

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Thu 9/10

8:33 pm-10:59 pm

Nonstop4h 26m

Ontario

Sun 9/13

7:13 pm-5:28 am

1 stop8h 15m

$244

ChicagoOntario

ORD Chicago O'Hare Intl - ONT Ontario

ORDONT

Chicago O'Hare Intl

Fri 10/23

7:35 am-12:21 pm

1 stop6h 46m

Ontario

Sun 10/25

11:15 pm-8:39 am

1 stop7h 24m

$257

ChicagoOntario

MDW Chicago Midway - ONT Ontario

MDWONT

Chicago Midway

Wed 8/26

9:25 am-2:05 pm

1 stop6h 40m

Ontario

Fri 8/28

11:55 pm-5:45 am

Nonstop3h 50m

$267

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/11

Showing 1-10 of 43 resultsSorted by cheapest first
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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 August.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice 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 FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Chicago-Ontario flight deals on Cheapflights vs. FlightHub >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 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 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

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

Currently, October is the cheapest month in which you can book a flight from Chicago to Ontario (average of $331). Flying from Chicago to Ontario in December is currently the most expensive (average of $576). 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 August 12, 2026.

Unlike in the morning, when flights are generally more expensive, you can save up to 41% on flights from Chicago to Ontario by exploring options for tickets at noon.

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

Airfare is below average for this route at the moment.
Chicago to Ontario flights typically cost between $244 and $740 in September.
The cheapest round-trip price found within the last 5 days was $146 on Frontier (Sep 10-Sep 16).

What’s the top layover airport for flights from Chicago to Ontario?

Share of 1-stop round-trip flights from Chicago to Ontario chosen by Cheapflights users in the past 12 months, using the same layover each way.

Phoenix (PHX) – chosen by Cheapflights users on 57% of 1-stop itineraries from Chicago to Ontario on Cheapflights.

What’s the cheapest layover airport for flights from Chicago to Ontario?

Average round-trip fare for 1-stop flights from Chicago to Ontario, chosen by Cheapflights users in the past 12 months, with the same layover each way.

Denver (DEN) is the most affordable 1-stop option, with an average round-trip price of $183.

What’s the fastest layover option from Chicago to Ontario?

Shortest average travel time for 1-stop one-way flights from Chicago to Ontario, based on itineraries clicked by Cheapflights users over the past 12 months, grouped by layover airport.

Flights via Denver (DEN) have the shortest average one-way travel time for 1-stop routes: 5h 30m.

Which airport typically offers the quickest layover for flights from Chicago to Ontario?

Average layover duration for 1-stop one-way flights from Chicago to Ontario, chosen by Cheapflights users in the last 12 months, grouped by stopover airport.

Flights via Denver (DEN) offer the fastest connection on this route, with an average layover time of 0h 55m.

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

Booking 41 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.

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
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 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 August 12, 2026.
Read through reviews of airlines operating flights from Chicago to Ontario, such as Southwest,United Airlines, andFrontier. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,220 reviews

Food

7.0

Overall

8.0

Comfort

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

Reviews

1 / 20
10.0
Excellent

Sarah,Aug 2024

MDW - AUS

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.
Southwest
8.0
Very good
4,220 reviews
Southwest
8.0
Very good
4,220 reviews

Food

7.0

Overall

8.0

Comfort

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

Reviews

1 / 20
10.0
Excellent

Sarah,Aug 2024

MDW - AUS

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.
United Airlines
7.4
Good
10,111 reviews
Southwest
8.0
Very good
4,220 reviews

Food

7.0

Overall

8.0

Comfort

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

Reviews

1 / 20
10.0
Excellent

Sarah,Aug 2024

MDW - AUS

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.
Frontier
5.6
Fair
2,701 reviews
Southwest
8.0
Very good
4,220 reviews

Food

7.0

Overall

8.0

Comfort

8.0

Boarding

8.1

Entertainment

7.5

Crew

8.6

Reviews

1 / 20
10.0
Excellent

Sarah,Aug 2024

MDW - AUS

My first time, surprisingly good! It was a good ride overall. Coming from Singapore, this budget flight is better than the budget airline for our national carrier Singapore Airlines.

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 4h 10m. United Airlines provides one of the quickest options available for as low as $188. There are 1701 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 $167. Additional round-trip tickets that might be worth considering are offered by Delta and Southwest, with the lowest prices starting at $236 and $268, respectively. Frontier is currently priced 61% 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 $86. Delta flights start at $109 while deals on American Airlines start at $119 one-way.

  • What are the cheapest flights from Chicago to Ontario?

    While on average a flight from Chicago to Ontario is generally $395, our data shows the cheapest flight currently is $137. When looking at the most popular route, (Chicago O'Hare Intl - Ontario), you can expect to pay $146 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, October is the cheapest month in which you can book a flight from Chicago to Ontario (average of $331). Flying from Chicago to Ontario in December is currently the most expensive (average of $576). 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 August 12, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$167Average$268FlexibilityNo cancel feeOn-time62%
DeltaCheapest$236Average$385FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$268Average$457FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$307Average$479FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$307Average$531FlexibilityNo cancel feeOn-time71%

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