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Ontario

$114+ 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 8/9. Fares are subject to change and may not be available on all flights or dates of travel.
CHI — ONT
Aug 4 — Aug 111
Mon 8/4
Mon 8/11
1 adult, Economy
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Cheapflights Tip: The best prices from Chicago to Ontario are usually found in September or November, 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 July 30, 2025.

Round-trip from

$236
(Flightnetwork)

One-way from

$114
(Trip.com)

Popular in

December

Cheapest in

September

Average price

$356

Good round-trip deal

$337 or less

Good one-way deal

$127 or less
From Chicago (CHI) to Ontario
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One-way flight from Chicago (CHI) to Ontario
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Highest demand for flights based on searches. 0% potential increase in price ($1 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($11 potential savings vs. average RT price).
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Average for round-trip flights in July 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 July 30, 2025.

This Flightnetwork deal was found by Cheapflights users on 7/30. 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 Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/169:55 amORD - ONT
1 stop11h 19mFrontier
Fri 8/2212:59 amONT - ORD
1 stop20h 40mFrontier
Deal found 7/30$236
This Mytrip deal was found by Cheapflights users on 7/29. 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.
Sat 8/92:44 pmMDW - ONT
1 stop11h 06mFrontier
Fri 8/1512:59 amONT - MDW
1 stop17h 55mFrontier
Deal found 7/29$238
This American Airlines deal was found by Cheapflights users on 7/29. 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.
Sat 10/47:34 amORD - ONT
1 stop12h 42mAmerican Airlines
Tue 10/71:00 pmONT - ORD
1 stop9h 30mAmerican Airlines
Deal found 7/29$283
This Delta deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/2011:00 amMDW - ONT
1 stop10h 15mDelta
Sat 9/2711:55 amONT - MDW
1 stop7h 15mDelta
Deal found 7/29$306
This Alaska Airlines deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/118:00 amORD - ONT
1 stop9h 17mAlaska Airlines
Wed 12/311:30 amONT - ORD
1 stop10h 29mAlaska Airlines
Deal found 7/29$306
This Delta deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/85:20 amORD - ONT
1 stop7h 06mDelta
Tue 12/211:29 amONT - ORD
1 stop10h 18mDelta
Deal found 7/29$307
This Southwest deal was found by Cheapflights users on 7/29. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/278:25 amMDW - ONT
Nonstop4h 10mSouthwest
Sat 10/48:05 amONT - MDW
Nonstop3h 50mSouthwest
Deal found 7/29$317
This United Airlines deal was found by Cheapflights users on 7/29. 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.
Sat 9/137:59 pmORD - ONT
Nonstop4h 31mUnited Airlines
Wed 9/177:00 amONT - ORD
Nonstop4h 03mUnited Airlines
Deal found 7/29$317

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 July 30, 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

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 8/16

9:55 am-7:14 pm

1 stop11h 19m

Ontario

Fri 8/22

12:59 am-11:39 pm

1 stop20h 40m

$236

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Sat 8/9

2:44 pm-11:50 pm

1 stop11h 06m

Ontario

Fri 8/15

12:59 am-8:54 pm

1 stop17h 55m

$238

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 10/4

7:34 am-6:16 pm

1 stop12h 42m

Ontario

Tue 10/7

1:00 pm-12:30 am

1 stop9h 30m

$283

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Tue 11/11

8:00 am-3:17 pm

1 stop9h 17m

Ontario

Wed 12/3

11:30 am-11:59 pm

1 stop10h 29m

$306

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Sat 9/20

11:00 am-7:15 pm

1 stop10h 15m

Ontario

Sat 9/27

11:55 am-9:10 pm

1 stop7h 15m

$306

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 11/8

5:20 am-10:26 am

1 stop7h 06m

Ontario

Wed 12/3

12:00 pm-11:53 pm

1 stop9h 53m

$307

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 9/13

7:59 pm-10:30 pm

Nonstop4h 31m

Ontario

Wed 9/17

7:00 am-1:03 pm

Nonstop4h 03m

$317

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Sat 9/27

8:25 am-10:35 am

Nonstop4h 10m

Ontario

Sat 10/4

8:05 am-1:55 pm

Nonstop3h 50m

$317

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Tue 10/14

6:00 am-12:37 pm

1 stop8h 37m

Ontario

Sat 10/25

1:31 pm-12:06 am

1 stop8h 35m

$318

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Sat 8/9

3:18 pm-9:52 pm

1 stop8h 34m

$114

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/28

Showing 1-10 of 20 results
1
2

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 July 25, 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 July 30, 2025.

Unlike in the afternoon, when flights are generally more expensive, you can save up to 28% 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 July 27, 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.

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

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.

Denver (DEN) – chosen by Cheapflights users on 97% 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.

Las Vegas (LAS) is the most affordable 1-stop option, with an average round-trip price of $113.

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: 6h 18m.

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 1h 50m.

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 July 30, 2025.
Read through reviews of airlines operating flights from Chicago to Ontario, such as Alaska Airlines, Southwest, and Delta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Entertainment

7.1

Food

7.1

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

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Entertainment

7.1

Food

7.1

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
4,241 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Entertainment

7.1

Food

7.1

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
7,980 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Entertainment

7.1

Food

7.1

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.8
Good
2,611 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Entertainment

7.1

Food

7.1

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
8,896 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Crew

8.5

Boarding

8.1

Comfort

7.8

Overall

8.0

Entertainment

7.1

Food

7.1

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 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.

  • 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 $236. Additional round-trip tickets that might be worth considering are offered by American Airlines and Alaska Airlines, with the lowest prices starting at $283 and $306, respectively. Frontier is currently priced 21% 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 $116. Alaska Airlines flights start at $144 while deals on American Airlines start at $146 one-way.

  • What are the cheapest flights from Chicago to Ontario?

    While on average a flight from Chicago to Ontario is generally $565, our data shows the cheapest flight currently is $102. When looking at the most popular route, (Chicago O'Hare Intl - Ontario), you can expect to pay $236 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 July 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$121Average$196FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$231Average$409FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$237Average$418FlexibilityNo cancel feeOn-time69%
DeltaCheapest$246Average$280FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$246Average$475FlexibilityNo cancel feeOn-time63%

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