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$49+ Cheap flights from Colorado 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 10/1. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ONT
Oct 23 — Oct 301
Thu 10/23
Thu 10/30
1 adult, Economy
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Cheap flight deals from Colorado to Ontario

Keep the following information in mind while searching for Colorado to Ontario flight deals. Data was last updated September 23, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$82
(CheapOair)

One-way from

$49
(CheapOair)

Popular in

June

Cheapest in

January

Average price

$177

Good round-trip deal

$126 or less

Good one-way deal

$86 or less
Provider with most accurate pricing for Denver Intl-Los Angeles flight deals.
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Provider most trusted by Cheapflights users for Denver Intl-Los Angeles flights.
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From Colorado to Ontario
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One-way flight from Colorado to Ontario
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Highest demand for flights based on searches. 8% potential increase in price ($17 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($4 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 Colorado to Ontario.
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Price to beat on a one-way flight from Colorado to Ontario.
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Find flight deals from Colorado to Ontario

Cheapest flights from Colorado to Ontario
Explore the most affordable flight options available from Colorado to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 23, 2025.

This CheapOair deal was found by Cheapflights users on 9/23. 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.
Fri 12/59:30 amDEN - ONT
Nonstop2h 27mFrontier
Mon 12/811:52 amONT - DEN
Nonstop2h 22mFrontier
Deal found 9/23$82
This Kiwi.com deal was found by Cheapflights users on 9/23. 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.
Sun 10/268:15 amDEN - ONT
Nonstop2h 20mFrontier
Sat 11/16:53 amONT - DEN
Nonstop2h 25mFrontier
Deal found 9/23$83
This CheapOair deal was found by Cheapflights users on 9/21. 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.
Wed 11/58:05 pmDEN - ONT
Nonstop2h 22mFrontier
Sun 11/96:45 amONT - DEN
Nonstop2h 25mFrontier
Deal found 9/21$84
This CheapOair deal was found by Cheapflights users on 9/23. 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 11/89:48 amDEN - ONT
Nonstop2h 22mFrontier
Tue 11/118:45 amONT - DEN
Nonstop2h 22mFrontier
Deal found 9/23$86
This Kiwi.com deal was found by Cheapflights users on 9/23. 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.
Thu 11/139:48 amDEN - ONT
Nonstop2h 22mFrontier
Mon 11/176:53 amONT - DEN
Nonstop2h 25mFrontier
Deal found 9/23$87
This CheapOair deal was found by Cheapflights users on 9/22. 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.
Sun 10/268:15 amDEN - ONT
Nonstop2h 20mFrontier
Mon 10/276:53 amONT - DEN
Nonstop2h 25mFrontier
Deal found 9/22$88
This Booking.com deal was found by Cheapflights users on 9/23. 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.
Sat 10/1110:29 pmDEN - ONT
Nonstop2h 21mFrontier
Mon 10/136:53 amONT - DEN
Nonstop2h 25mFrontier
Deal found 9/23$89
This Priceline deal was found by Cheapflights users on 9/23. 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 10/2310:29 pmDEN - ONT
Nonstop2h 21mFrontier
Sat 11/16:53 amONT - DEN
Nonstop2h 25mFrontier
Deal found 9/23$90
This Kiwi.com deal was found by Cheapflights users on 9/23. 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.
Tue 9/306:29 pmDEN - ONT
Nonstop2h 25mFrontier
Tue 10/77:04 amONT - DEN
Nonstop2h 27mFrontier
Deal found 9/23$93
This Priceline deal was found by Cheapflights users on 9/22. 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.
Wed 10/16:29 pmDEN - ONT
Nonstop2h 25mFrontier
Sat 10/48:59 pmONT - DEN
Nonstop2h 27mFrontier
Deal found 9/22$94
This CheapOair deal was found by Cheapflights users on 9/23. 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.
Thu 10/26:00 amDEN - ONT
Nonstop2h 23mFrontier
Mon 10/136:53 amONT - DEN
Nonstop2h 25mFrontier
Deal found 9/23$97
This Priceline deal was found by Cheapflights users on 9/21. 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.
Tue 9/306:29 pmDEN - ONT
Nonstop2h 25mFrontier
Sat 10/48:59 pmONT - DEN
Nonstop2h 27mFrontier
Deal found 9/21$98

Cheapflights Fare Finder

 
Customize your flight search to find flights from Colorado 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 September 23, 2025.
Use the filters below to find and compare flights from Colorado to Ontario that are best for you.

Fly from

Colorado

Fly to

Ontario

Route

Depart

Return

Price

DenverOntario

DEN - ONT

DENONT

Denver Intl

Wed 10/1

10:29 pm-8:26 am

1 stop10h 57m

Ontario

Thu 10/2

7:30 pm-4:00 am

1 stop7h 30m

$144

DenverOntario

DEN - ONT

DENONT

Denver Intl

Wed 12/10

8:45 pm-10:05 pm

Nonstop2h 20m

Ontario

Thu 12/11

5:45 am-9:00 am

Nonstop2h 15m

$157

DenverOntario

DEN - ONT

DENONT

Denver Intl

Mon 12/8

8:45 pm-10:05 pm

Nonstop2h 20m

Ontario

Tue 12/9

5:45 am-9:00 am

Nonstop2h 15m

$157

DenverOntario

DEN - ONT

DENONT

Denver Intl

Mon 10/27

10:25 pm-11:40 pm

Nonstop2h 15m

Ontario

Tue 10/28

3:15 pm-6:30 pm

Nonstop2h 15m

$157

DenverOntario

DEN - ONT

DENONT

Denver Intl

Thu 10/16

1:00 pm-2:15 pm

Nonstop2h 15m

Ontario

Sat 10/18

11:10 am-7:15 pm

1 stop7h 05m

$207

DenverOntario

DEN - ONT

DENONT

Denver Intl

Fri 10/31

6:23 pm-9:20 pm

1 stop3h 57m

Ontario

Thu 11/6

1:15 pm-7:01 pm

1 stop4h 46m

$217

DenverOntario

DEN - ONT

DENONT

Denver Intl

Sat 11/1

6:25 am-2:01 pm

1 stop8h 36m

Ontario

Sat 11/8

1:15 pm-7:01 pm

1 stop4h 46m

$217

DenverOntario

DEN - ONT

DENONT

Denver Intl

Fri 12/12

6:20 pm-11:59 pm

1 stop6h 39m

Ontario

Tue 12/16

6:00 am-11:10 am

1 stop4h 10m

$217

DenverOntario

DEN - ONT

DENONT

Denver Intl

Fri 10/31

6:23 pm-9:20 pm

1 stop3h 57m

Ontario

Tue 11/11

6:00 am-11:07 am

1 stop4h 07m

$217

DenverOntario

DEN - ONT

DENONT

Denver Intl

Wed 12/3

6:20 pm-11:59 pm

1 stop6h 39m

Ontario

Sun 12/7

6:00 am-11:10 am

1 stop4h 10m

$217

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/21

Showing 1-10 of 60 results
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Best time to book a flight from Colorado to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Colorado 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 Colorado to Ontario

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

Currently, August is the cheapest month in which you can book a flight from Colorado to Ontario (average of $246). Flying from Colorado 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 CO to ONT?

Find hourly flight availability from Colorado 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 September 23, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Colorado to Ontario as you normally would.

Related info for your journey

Find useful and relevant information for your journey from Colorado 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 Colorado?

    If you book a flight to Ontario from Colorado, you will be flying to Ontario, which is the city’s only airport. Ontario (ONT) is located 3.1 mi from the center of Ontario.

  • How popular is this Colorado to Ontario flight route?

    The Colorado to Ontario flight path was viewed by 65 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • How long is the flight from Colorado to Ontario?

    For as low as $157, Frontier can have you in Ontario from Colorado in 2h 20m. The distance between Colorado and Ontario is about 817 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines to fly from Colorado to Ontario one-way?

    The cheapest airlines for a one-way flight from Colorado to Ontario are Southwest ($79), United Airlines ($79), and Delta ($109).

  • What are the most popular routes from Colorado to Ontario?

    While some choose either Colorado Springs - Ontario or Grand Junction Regnl - Ontario, Denver Intl - Ontario is the most popular route from Colorado to Ontario.

  • What are the most reliable airlines from Colorado to Ontario?

    No one likes to see their flight delayed. When booking a flight from Colorado to Ontario consider choosing Air Canada (80%), Frontier (79%) or United Airlines (76%) as they are the most reliable in getting you off to your destination on time.

  • What are the cheapest flights from Colorado to Ontario?

    While on average a flight from Colorado to Ontario is generally $154, our data shows the cheapest flight currently is $39. When looking at the most popular route, (Denver Intl - Ontario), you can expect to pay $82 for that flight.

  • Can I find deals for flights from Colorado to Ontario that include hotel bookings?

    Yes. In addition to deals on Colorado to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Colorado to Ontario?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Colorado to Ontario.

  • Can I find deals for business class flights from Colorado to Ontario?

    Yes. Cheapflights offers flight deals from Colorado 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 Colorado to Ontario?

    Currently, August is the cheapest month in which you can book a flight from Colorado to Ontario (average of $246). Flying from Colorado 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 Colorado 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 Colorado to Ontario

Discover the top 5 airlines that operate flights from Colorado 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 September 23, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$62Average$149FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$121Average$314FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$137Average$341FlexibilityNo cancel feeOn-time69%
DeltaCheapest$177Average$288FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$218Average$348FlexibilityNo cancel feeOn-time71%

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