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$118+ 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 7/2. Fares are subject to change and may not be available on all flights or dates of travel.
CHI — ONT
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
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 Tuesday

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 June 12, 2025.

Round-trip from

$244
(FlightHub)

One-way from

$118
(Trip.com)

Popular in

December

Cheapest in

November

Average price

$329

Good round-trip deal

$227 or less

Good one-way deal

$152 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, 2% 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 June 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 June 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.
Fri 8/2212:31 pmORD - ONT
1 stop8h 03mFrontier
Sat 8/3012:59 amONT - ORD
1 stop7h 38mFrontier
Deal found 6/10$244
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/142:44 pmMDW - ONT
1 stop11h 06mFrontier
Sun 8/1712:59 amONT - MDW
1 stop8h 42mFrontier
Deal found 6/12$255
This Alaska Airlines 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/315:57 pmORD - ONT
1 stop28h 51mAlaska Airlines
Tue 11/116:00 amONT - ORD
1 stop15h 59mAlaska Airlines
Deal found 6/10$298
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.
Tue 8/121:30 pmORD - ONT
2 stops12h 10mDelta
Wed 8/139:50 amONT - ORD
1 stop6h 17mDelta
Deal found 6/10$324
This KAYAK 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 KAYAK is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/246:55 pmORD - ONT
1 stop7h 00mSouthwest
Fri 7/255:40 amONT - ORD
1 stop16h 00mSouthwest
Deal found 6/11$335
This Hawaiian Airlines 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/213:20 pmORD - ONT
1 stop10h 39mHawaiian Airlines
Tue 8/2611:39 amONT - ORD
1 stop10h 20mHawaiian Airlines
Deal found 6/12$365
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.
Tue 8/191:08 pmMDW - ONT
2 stops11h 34mDelta
Sun 8/2410:00 pmONT - MDW
2 stops8h 35mDelta
Deal found 6/10$376
This United Airlines 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/227:40 pmORD - ONT
Nonstop4h 31mUnited Airlines
Tue 7/297:00 amONT - ORD
Nonstop4h 03mUnited Airlines
Deal found 6/10$397
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.
Sat 7/1212:30 pmMDW - ONT
1 stop5h 30mSouthwest
Sat 7/196:00 amONT - MDW
Nonstop3h 50mSouthwest
Deal found 6/12$403

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 June 12, 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

Fri 8/22

12:31 pm-6:34 pm

1 stop8h 03m

Ontario

Sat 8/30

12:59 am-10:37 am

1 stop7h 38m

$244

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Thu 8/14

2:44 pm-11:50 pm

1 stop11h 06m

Ontario

Sun 8/17

12:59 am-11:41 am

1 stop8h 42m

$255

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Tue 8/12

1:30 pm-11:40 pm

2 stops12h 10m

Ontario

Wed 8/13

9:50 am-6:07 pm

1 stop6h 17m

$324

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Thu 7/24

6:55 pm-11:55 pm

1 stop7h 00m

Ontario

Fri 7/25

5:40 am-11:40 pm

1 stop16h 00m

$335

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Tue 8/19

1:08 pm-10:42 pm

2 stops11h 34m

Ontario

Sun 8/24

10:00 pm-8:35 am

2 stops8h 35m

$376

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Fri 8/8

6:00 am-1:26 pm

1 stop9h 26m

Ontario

Wed 8/13

2:21 pm-11:59 pm

1 stop7h 38m

$384

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Tue 9/9

1:36 pm-9:29 pm

1 stop9h 53m

Ontario

Sun 9/14

10:56 pm-12:10 pm

1 stop11h 14m

$386

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Tue 7/22

7:40 pm-10:11 pm

Nonstop4h 31m

Ontario

Tue 7/29

7:00 am-1:03 pm

Nonstop4h 03m

$397

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Tue 7/8

6:00 am-2:46 pm

1 stop10h 46m

Ontario

Thu 8/7

10:03 am-10:30 pm

2 stops10h 27m

$399

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Sat 7/12

12:30 pm-4:00 pm

1 stop5h 30m

Ontario

Sat 7/19

6:00 am-11:50 am

Nonstop3h 50m

$403

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/10

Showing 1-10 of 22 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 June 9, 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 June 12, 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 June 8, 2025.

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

Rainfall in Ontario by month

Plan your trip to Ontario by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Ontario ranges from 0.1 - 3.4 inches per month. February is typically the wettest month, when rainfall can reach 3.4 in. June is typically the driest time to visit Ontario when rainfall is around 0.1 in.

Temperature in Ontario by month

Plan your trip to Ontario by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Ontario, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 78.8 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 53.6 F).

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 June 12, 2025.
Peruse reviews from past customers who have flown with Alaska Airlines, Southwest and Delta from Chicago to Ontario to help guide your decision. In addition to providing an overall rating, 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

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

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

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

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

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

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

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

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

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

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

Overall

8.0

Entertainment

7.1

Food

7.1

Boarding

8.1

Comfort

7.8

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 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 $244. Additional round-trip tickets that might be worth considering are offered by Alaska Airlines and Delta, with the lowest prices starting at $298 and $324, respectively. Frontier is currently priced 17% 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 $122. Alaska Airlines flights start at $137 while deals on Hawaiian Airlines start at $141 one-way.

  • What are the cheapest flights from Chicago to Ontario?

    While on average a flight from Chicago to Ontario is generally $270, our data shows the cheapest flight currently is $113. When looking at the most popular route, (Chicago O'Hare Intl - Ontario), you can expect to pay $290 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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$121Average$205FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$231Average$388FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$237Average$398FlexibilityNo cancel feeOn-time69%
DeltaCheapest$246Average$378FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$246Average$463FlexibilityNo cancel feeOn-time63%

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