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$62+ 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 10/7. Fares are subject to change and may not be available on all flights or dates of travel.
CHI — ONT
oct. 11 — oct. 181
sáb. 10/11
sáb. 10/18
1 adult, Economy
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Cheapflights Tip: The best prices from Chicago to Ontario are usually found in November or September, booked 36 days in advance, depart on a Tuesday or Thursday and return on a Thursday

Cheap 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 septiembre 11, 2025.

Round-trip from

$129
(Kiwi.com)

One-way from

$62
(Trip.com)

Popular in

December

Cheapest in

November

Average price

$245

Good round-trip deal

$329 or less

Good one-way deal

$205 or less
From Chicago (CHI) to Ontario
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One-way flight from Chicago (CHI) to Ontario
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High demand for flights, 0% potential price rise
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Cheapest flight prices on average. 3% potential price decrease ($12 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Price to beat on a round-trip flight from Chicago (CHI) to Ontario.
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Price to beat on a one-way flight from Chicago (CHI) to Ontario.
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Find 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 septiembre 11, 2025.

This Kiwi.com deal was found by Cheapflights users on 9/9. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 10/157:15 amORD - ONT
1 stop18h 35mFrontier
mié. 11/126:53 amONT - ORD
1 stop15h 19mFrontier
Deal found 9/9$129
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 11/17:15 amORD - ONT
1 stop18h 35mFrontier
mié. 11/56:53 amONT - ORD
1 stop15h 19mFrontier
Deal found 9/10$132
This Kiwi.com deal was found by Cheapflights users on 9/9. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mié. 10/157:15 amORD - ONT
1 stop18h 35mFrontier
sáb. 11/156:53 amONT - ORD
1 stop15h 19mFrontier
Deal found 9/9$143
This CheapOair deal was found by Cheapflights users on 9/10. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 11/17:15 amORD - ONT
1 stop5h 55mFrontier
dom. 11/25:53 amONT - ORD
1 stop15h 19mFrontier
Deal found 9/10$148
This Booking.com deal was found by Cheapflights users on 9/11. 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.
mié. 10/297:20 amORD - ONT
1 stop18h 30mFrontier
sáb. 11/112:05 pmONT - ORD
1 stop10h 07mFrontier
Deal found 9/11$149
This CheapOair deal was found by Cheapflights users on 9/10. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 11/712:30 pmMDW - ONT
1 stop24h 40mFrontier
dom. 11/96:53 amONT - MDW
1 stop26h 37mFrontier
Deal found 9/10$150
This Booking.com deal was found by Cheapflights users on 9/11. 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.
vie. 10/3112:30 pmMDW - ONT
1 stop24h 40mFrontier
dom. 11/25:53 amONT - MDW
1 stop26h 37mFrontier
Deal found 9/11$151
This Kiwi.com deal was found by Cheapflights users on 9/11. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
mar. 10/287:14 amORD - ONT
1 stop18h 36mFrontier
mar. 11/46:53 amONT - ORD
1 stop15h 19mFrontier
Deal found 9/11$152
This CheapOair deal was found by Cheapflights users on 9/10. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 11/77:20 amORD - ONT
1 stop13h 08mFrontier
dom. 11/96:53 amONT - ORD
1 stop15h 26mFrontier
Deal found 9/10$153
This CheapOair deal was found by Cheapflights users on 9/10. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 10/210:13 amMDW - ONT
1 stop7h 26mFrontier
dom. 10/58:59 pmONT - MDW
1 stop16h 54mFrontier
Deal found 9/10$154
This Booking.com deal was found by Cheapflights users on 9/11. 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.
jue. 9/184:03 pmORD - ONT
1 stop28h 32mFrontier
vie. 9/268:59 pmONT - ORD
1 stop22h 29mFrontier
Deal found 9/11$154
This Booking.com deal was found by Cheapflights users on 9/11. 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.
vie. 10/109:00 amMDW - ONT
1 stop9h 28mFrontier
dom. 10/126:53 amONT - MDW
1 stop15h 43mFrontier
Deal found 9/11$155

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 septiembre 11, 2025.
Use the filters below to find and compare flights from Chicago to Ontario that are best for you.

Fly from

Chicago

Fly to

Ontario

Route

Depart

Return

Price

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

vie. 10/31

12:30 pm-11:10 am

1 stop24h 40m

Ontario

dom. 11/2

5:53 am-10:30 am

1 stop26h 37m

$151

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

vie. 10/31

12:30 pm-11:10 am

1 stop24h 40m

Ontario

dom. 11/9

6:53 am-11:30 am

1 stop26h 37m

$151

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

jue. 10/16

10:30 am-5:54 pm

1 stop9h 24m

Ontario

lun. 10/20

6:53 am-12:24 am

1 stop15h 31m

$154

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

lun. 9/22

9:54 pm-9:56 pm

1 stop26h 02m

Ontario

lun. 9/29

4:08 pm-9:28 pm

1 stop27h 20m

$154

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

jue. 10/16

6:24 pm-11:50 pm

1 stop7h 26m

Ontario

dom. 10/26

6:53 am-11:16 am

1 stop26h 23m

$168

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

jue. 10/16

10:30 am-5:54 pm

1 stop9h 24m

Ontario

sáb. 10/18

8:34 am-11:20 pm

1 stop12h 46m

$168

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

dom. 10/19

10:30 am-5:49 pm

1 stop9h 19m

Ontario

dom. 10/26

6:53 am-11:16 am

1 stop26h 23m

$186

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

dom. 10/26

10:30 am-5:49 pm

1 stop9h 19m

Ontario

jue. 10/30

1:46 pm-12:37 pm

1 stop20h 51m

$197

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

sáb. 1/10

7:45 am-3:12 pm

1 stop9h 27m

Ontario

lun. 1/12

11:30 am-11:59 pm

1 stop10h 29m

$214

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

mar. 2/24

2:05 pm-7:47 pm

1 stop7h 42m

Ontario

jue. 2/26

6:55 pm-5:04 am

1 stop8h 09m

$214

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/11

Showing 1-10 of 45 results
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The best insider tips for Chicago to Ontario 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 Chicago to Ontario trip
Airports
MDW

Use the Orange Line train for a quick, affordable trip to MDW, taking less than 30 minutes from downtown Chicago.

Read more about MDWby Ramsey Qubein
ONT

Consider renting a car at ONT for easy access to Southern California destinations like Palm Springs and Big Bear.

Read more about ONTby Bill Fink
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 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

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

Use this chart to determine the optimal time to book a round-trip flight from Chicago to Ontario. Price data was last updated on August 29, 2025.

Booking 36 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.

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

Currently, August is the cheapest month in which you can book a flight from Chicago to Ontario (average of $246). Flying from Chicago to Ontario in March is currently the most expensive (average of $328). 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 septiembre 11, 2025.

Unlike in the morning, when flights are generally more expensive, you can save up to 24% on flights from Chicago to Ontario by exploring options for tickets in the evening.

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

Use this chart to determine the cheapest time to fly round-trip from Chicago to Ontario. Price data was last updated on September 7, 2025.

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

Weekly flight availability from Chicago to Ontario

Explore weekly flight availability from Chicago to Ontario. 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 septiembre 11, 2025.

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

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 septiembre 11, 2025.
Read through reviews of airlines operating flights from Chicago to Ontario, such as Southwest, Delta, and United Airlines. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,248 reviews

Crew

8.6

Overall

8.0

Entertainment

7.5

Comfort

8.0

Food

7.0

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,248 reviews
Southwest
8.0
Very good
4,248 reviews

Crew

8.6

Overall

8.0

Entertainment

7.5

Comfort

8.0

Food

7.0

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Delta
8.0
Very good
7,960 reviews
Southwest
8.0
Very good
4,248 reviews

Crew

8.6

Overall

8.0

Entertainment

7.5

Comfort

8.0

Food

7.0

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
8,937 reviews
Southwest
8.0
Very good
4,248 reviews

Crew

8.6

Overall

8.0

Entertainment

7.5

Comfort

8.0

Food

7.0

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,248 reviews

Crew

8.6

Overall

8.0

Entertainment

7.5

Comfort

8.0

Food

7.0

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Frontier
5.8
Fair
3,177 reviews
Southwest
8.0
Very good
4,248 reviews

Crew

8.6

Overall

8.0

Entertainment

7.5

Comfort

8.0

Food

7.0

Boarding

8.1

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

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 8h 27m. Frontier provides one of the quickest options available for as low as $189. There are 1695 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 $124. Additional round-trip tickets that might be worth considering are offered by American Airlines and United Airlines, with the lowest prices starting at $231 and $237, respectively. Frontier is currently priced 60% 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 $79. Southwest flights start at $92 while deals on United Airlines start at $98 one-way.

  • What are the cheapest flights from Chicago to Ontario?

    While on average a flight from Chicago to Ontario is generally $351, our data shows the cheapest flight currently is $148. When looking at the most popular route, (Chicago O'Hare Intl - Ontario), you can expect to pay $148 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, August is the cheapest month in which you can book a flight from Chicago to Ontario (average of $246). Flying from Chicago to Ontario in March is currently the most expensive (average of $328). 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 septiembre 11, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$124Average$212FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$231Average$429FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$237Average$432FlexibilityNo cancel feeOn-time69%
DeltaCheapest$246Average$256FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$246Average$464FlexibilityNo cancel feeOn-time63%

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