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$48+ 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 12/5. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ONT
Dec 13 — Dec 201
Sat 12/13
Sat 12/20
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 November 13, 2025.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$79
(Frontier)

One-way from

$48
(Kiwi.com)

Popular in

June

Cheapest in

February

Average price

$218

Good round-trip deal

$136 or less

Good one-way deal

$92 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 ($16 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($4 potential savings vs. average RT price).
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Average for round-trip flights in November 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 November 13, 2025.

This Frontier deal was found by Cheapflights users on 11/12. 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.
Fri 12/512:58 pmDEN - ONT
Nonstop2h 27mFrontier
Sat 12/63:20 pmONT - DEN
Nonstop2h 20mFrontier
Deal found 11/12$79
This Super.com deal was found by Cheapflights users on 11/11. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/252:00 pmDEN - ONT
Nonstop2h 26mFrontier
Wed 11/2612:58 amONT - DEN
Nonstop2h 22mFrontier
Deal found 11/11$80
This Booking.com deal was found by Cheapflights users on 11/12. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/252:00 pmDEN - ONT
Nonstop2h 26mFrontier
Fri 11/287:48 pmONT - DEN
Nonstop2h 27mFrontier
Deal found 11/12$81
This Super.com deal was found by Cheapflights users on 11/12. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/141:40 pmDEN - ONT
Nonstop2h 26mFrontier
Sun 12/216:45 amONT - DEN
Nonstop2h 21mFrontier
Deal found 11/12$84
This Flightnetwork deal was found by Cheapflights users on 11/11. 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 Flightnetwork is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/1312:58 pmDEN - ONT
Nonstop2h 27mFrontier
Mon 12/155:18 pmONT - DEN
1 stop20h 35mFrontier
Deal found 11/11$85
This CheapOair deal was found by Cheapflights users on 11/12. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/1212:58 pmDEN - ONT
Nonstop2h 27mFrontier
Mon 12/155:18 pmONT - DEN
1 stop9h 40mFrontier
Deal found 11/12$88
This Mytrip deal was found by Cheapflights users on 11/12. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/612:58 pmDEN - ONT
Nonstop2h 27mFrontier
Thu 12/112:59 pmONT - DEN
1 stop11h 59mFrontier
Deal found 11/12$91
This Frontier deal was found by Cheapflights users on 11/12. 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 12/119:42 amDEN - ONT
Nonstop2h 27mFrontier
Mon 12/153:20 pmONT - DEN
Nonstop2h 20mFrontier
Deal found 11/12$92
This Frontier deal was found by Cheapflights users on 11/12. 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 11/2710:29 pmDEN - ONT
Nonstop2h 28mFrontier
Thu 12/47:33 pmONT - DEN
1 stop11h 12mFrontier
Deal found 11/12$93
This CheapOair deal was found by Cheapflights users on 11/11. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/71:40 pmDEN - ONT
Nonstop2h 26mFrontier
Thu 12/1112:04 pmONT - DEN
Nonstop2h 20mFrontier
Deal found 11/11$94
This Delta deal was found by Cheapflights users on 11/13. 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.
Mon 12/86:00 pmCOS - ONT
1 stop6h 58mDelta
Mon 12/154:49 pmONT - COS
1 stop4h 36mDelta
Deal found 11/13$197
This Delta deal was found by Cheapflights users on 11/13. 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.
Thu 12/46:00 pmCOS - ONT
1 stop6h 58mDelta
Wed 12/104:49 pmONT - COS
1 stop4h 36mDelta
Deal found 11/13$198

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 November 13, 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

Mon 11/24

10:29 pm-11:57 pm

Nonstop2h 28m

Ontario

Sun 11/30

12:58 am-4:20 am

Nonstop2h 22m

$163

DenverOntario

DEN - ONT

DENONT

Denver Intl

Wed 12/17

8:15 am-9:40 am

Nonstop2h 25m

Ontario

Thu 12/18

2:15 pm-5:25 pm

Nonstop2h 10m

$164

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 1/6

3:46 pm-12:14 am

1 stop9h 28m

Ontario

Tue 1/13

4:03 pm-11:35 pm

1 stop6h 32m

$170

DenverOntario

DEN - ONT

DENONT

Denver Intl

Sat 12/13

6:22 pm-9:55 pm

1 stop4h 33m

Ontario

Mon 12/15

6:00 am-11:09 am

1 stop4h 09m

$197

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 1/27

7:00 am-12:16 pm

1 stop6h 16m

Ontario

Sun 2/1

7:30 am-5:34 pm

1 stop9h 04m

$197

DenverOntario

DEN - ONT

DENONT

Denver Intl

Wed 1/28

6:29 am-1:56 pm

1 stop8h 27m

Ontario

Sun 2/1

7:30 am-5:34 pm

1 stop9h 04m

$197

DenverOntario

DEN - ONT

DENONT

Denver Intl

Sun 11/23

10:00 am-11:28 am

Nonstop2h 28m

Ontario

Sun 11/30

5:06 pm-3:58 am

1 stop9h 52m

$200

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 1/13

11:23 am-12:47 pm

Nonstop2h 24m

Ontario

Tue 3/31

5:10 am-8:32 am

Nonstop2h 22m

$207

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 1/6

5:18 am-12:17 pm

1 stop7h 59m

Ontario

Tue 1/13

1:24 pm-4:43 pm

Nonstop2h 19m

$224

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Wed 12/10

1:15 pm-4:09 pm

1 stop3h 54m

Ontario

Wed 12/17

6:00 am-12:40 pm

1 stop5h 40m

$229

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/12

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, January is the cheapest month in which you can book a flight from Colorado to Ontario (average of $37). Flying from Colorado to Ontario in June is currently the most expensive (average of $97). 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 November 13, 2025.

It’s optimal to fly from Colorado to Ontario in the evening. By choosing this option you can save up to 36% on the cost of your flight, compared to a flight in the morning.

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

Use this chart to determine the cheapest time to fly round-trip from Colorado to Ontario. Price data was last updated on December 16, 2024.

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

Weekly flight availability from Colorado to Ontario

Explore weekly flight availability from Colorado 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 November 13, 2025.

The most flights from USCO to ONT are scheduled on a Thursday (10 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (6 on average).

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 56 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 $164, Frontier can have you in Ontario from Colorado in 2h 25m. 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 United Airlines ($59), Southwest ($79), and Alaska Airlines ($85).

  • 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 Frontier (88%), Air Canada (85%) or United Airlines (77%) 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 $190, our data shows the cheapest flight currently is $34. When looking at the most popular route, (Denver Intl - Ontario), you can expect to pay $57 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, January is the cheapest month in which you can book a flight from Colorado to Ontario (average of $37). Flying from Colorado to Ontario in June is currently the most expensive (average of $97). 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

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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 November 13, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$64Average$155FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$122Average$316FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$135Average$352FlexibilityNo cancel feeOn-time69%
DeltaCheapest$177Average$288FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$218Average$346FlexibilityNo cancel feeOn-time71%

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