HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Ontario

$53+ 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 9/4. Fares are subject to change and may not be available on all flights or dates of travel.
CHI — ONT
Jul 6 — Jul 131
Sun 7/6
Sun 7/13
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

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”

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 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 Friday

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 1, 2025.

Round-trip from

$114
(Priceline)

One-way from

$53
(Priceline)

Popular in

December

Cheapest in

November

Average price

$320

Good round-trip deal

$502 or less

Good one-way deal

$198 or less
From Chicago (CHI) to Ontario
Search Deals
One-way flight from Chicago (CHI) to Ontario
Search Deals
High demand for flights, 1% potential price rise
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($12 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 2025
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

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 1, 2025.

This Priceline deal was found by Cheapflights users on 6/29. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1810:18 amMDW - ONT
1 stop7h 06mFrontier
Mon 9/2212:19 pmONT - MDW
1 stop6h 33mFrontier
Deal found 6/29$114
This Priceline deal was found by Cheapflights users on 6/29. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1810:42 amORD - ONT
1 stop11h 12mFrontier
Mon 9/2212:19 pmONT - ORD
1 stop9h 39mFrontier
Deal found 6/29$130

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 1, 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

Thu 9/18

10:18 am-3:24 pm

1 stop7h 06m

Ontario

Mon 9/22

12:19 pm-8:52 pm

1 stop6h 33m

$114

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Thu 9/18

10:42 am-7:54 pm

1 stop11h 12m

Ontario

Mon 9/22

12:19 pm-11:58 pm

1 stop9h 39m

$130

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Thu 9/4

10:18 am-3:24 pm

1 stop7h 06m

$53

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Mon 9/15

6:00 am-9:57 am

1 stop5h 57m

$69

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Wed 7/30

7:08 am-6:27 pm

1 stop13h 19m

$115

ChicagoOntario

ORD - ONT

ORDONT

Chicago O'Hare Intl

Mon 9/8

7:59 pm-10:30 pm

Nonstop4h 31m

$149

ChicagoOntario

MDW - ONT

MDWONT

Chicago Midway

Mon 9/15

8:20 pm-10:30 pm

Nonstop4h 10m

$149

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/30

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 27, 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 1, 2025.

Unlike in the afternoon, when flights are generally more expensive, you can save up to 30% 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 29, 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.

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

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 1, 2025.
Read through reviews of airlines operating flights from Chicago to Ontario, such as Southwest, United Airlines, and Frontier. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,273 reviews

Boarding

8.2

Crew

8.6

Entertainment

7.6

Overall

8.0

Food

7.0

Comfort

8.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Southwest
8.0
Very good
4,273 reviews
Southwest
8.0
Very good
4,273 reviews

Boarding

8.2

Crew

8.6

Entertainment

7.6

Overall

8.0

Food

7.0

Comfort

8.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
United Airlines
7.4
Good
8,858 reviews
Southwest
8.0
Very good
4,273 reviews

Boarding

8.2

Crew

8.6

Entertainment

7.6

Overall

8.0

Food

7.0

Comfort

8.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Frontier
5.9
Fair
3,291 reviews
Southwest
8.0
Very good
4,273 reviews

Boarding

8.2

Crew

8.6

Entertainment

7.6

Overall

8.0

Food

7.0

Comfort

8.0

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.

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 is the cheapest airline to fly from Chicago to Ontario round-trip?

    Flying on Frontier is currently your cheapest option to Ontario, with prices starting at $114. 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 $53. United Airlines flights start at $149 while deals on Southwest start at $149 one-way.

  • What are the cheapest flights from Chicago to Ontario?

    While on average a flight from Chicago to Ontario is generally $456, our data shows the cheapest flight currently is $135. When looking at the most popular route, (Chicago O'Hare Intl - Ontario), you can expect to pay $203 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

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 Chicago to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
O'Hare Intl to Las Vegas flights
O'Hare Intl to Los Angeles flights
O'Hare Intl to San Francisco flights
O'Hare Intl to San Diego flights
O'Hare Intl to Santa Ana flights
O'Hare Intl to Ontario flights
Midway to Las Vegas flights
O'Hare Intl to Burbank flights
St. Louis to Las Vegas flights
Midway to San Francisco flights
O'Hare Intl to Reno flights
O'Hare Intl to Oakland flights
Midway to Los Angeles flights
O'Hare Intl to Sacramento flights
O'Hare Intl to San Jose flights
O'Hare Intl to Palm Springs flights
St. Louis to Los Angeles flights
St. Louis to San Francisco flights
Rockford to Las Vegas flights
Midway to San Diego flights
St. Louis to San Diego flights
Midway to Santa Ana flights
Midway to Reno flights
Midway to Long Beach flights
O'Hare Intl to Fresno flights
St. Louis to Ontario flights
Midway to San Jose flights
Midway to Ontario flights
O'Hare Intl to Long Beach flights
Midway to Sacramento flights
Midway to Palm Springs flights
Midway to Oakland flights
Peoria to San Diego flights
Moline to Las Vegas flights
Peoria to Las Vegas flights
Moline to San Jose flights
St. Louis to Santa Ana flights
O'Hare Intl to Monterey flights
St. Louis to Reno flights
O'Hare Intl to Santa Barbara flights
O'Hare Intl to Medford flights
Moline to Ontario flights
Peoria to Palm Springs flights
St. Louis to Sacramento flights
Midway to Burbank flights
Moline to Los Angeles flights
Decatur to Las Vegas flights
Evansville to Las Vegas flights
O'Hare Intl to San Luis Obispo flights
Bloomington to Las Vegas flights

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 1, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$122Average$199FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$231Average$399FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$237Average$405FlexibilityNo cancel feeOn-time69%
DeltaCheapest$246Average$283FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$246Average$477FlexibilityNo cancel feeOn-time63%

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.