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$42+ 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 2/9. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ONT
Jan 29 — Feb 51
Thu 1/29
Thu 2/5
1 adult, Economy
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Cheap 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 December 30, 2025.

This Kiwi.com deal was found by Cheapflights users on 12/30. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/3110:32 pmDEN - ONT
Nonstop2h 27mFrontier
Wed 1/77:00 amONT - DEN
Nonstop2h 22mFrontier
Deal found 12/30$275
This Cheapflightsfares deal was found by Cheapflights users on 12/28. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/3010:32 pmDEN - ONT
Nonstop2h 27mFrontier
Tue 1/67:00 amONT - DEN
Nonstop2h 22mFrontier
Deal found 12/28$298
This Frontier deal was found by Cheapflights users on 12/28. 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.
Wed 12/3110:32 pmDEN - ONT
Nonstop2h 27mFrontier
Tue 1/67:00 amONT - DEN
Nonstop2h 22mFrontier
Deal found 12/28$299
This Frontier deal was found by Cheapflights users on 12/29. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/3110:32 pmDEN - ONT
Nonstop2h 27mFrontier
Fri 1/96:00 amONT - DEN
Nonstop2h 26mFrontier
Deal found 12/29$319
This Cheapflightsfares deal was found by Cheapflights users on 12/28. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/2910:32 pmDEN - ONT
Nonstop2h 27mFrontier
Sun 1/116:00 amONT - DEN
Nonstop2h 26mFrontier
Deal found 12/28$323
This Frontier deal was found by Cheapflights users on 12/29. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/2910:32 pmDEN - ONT
Nonstop2h 27mFrontier
Tue 1/67:00 amONT - DEN
Nonstop2h 22mFrontier
Deal found 12/29$329
This Kiwi.com deal was found by Cheapflights users on 12/29. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/3010:32 pmDEN - ONT
Nonstop2h 27mFrontier
Wed 1/77:00 amONT - DEN
Nonstop2h 22mFrontier
Deal found 12/29$331
This Frontier deal was found by Cheapflights users on 12/29. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/2910:32 pmDEN - ONT
Nonstop2h 27mFrontier
Fri 1/96:00 amONT - DEN
Nonstop2h 26mFrontier
Deal found 12/29$349
This Frontier deal was found by Cheapflights users on 12/29. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/3110:32 pmDEN - ONT
Nonstop2h 27mFrontier
Mon 1/56:45 amONT - DEN
Nonstop2h 21mFrontier
Deal found 12/29$350
This Kiwi.com deal was found by Cheapflights users on 12/29. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/3010:32 pmDEN - ONT
Nonstop2h 27mFrontier
Thu 1/86:00 amONT - DEN
Nonstop2h 26mFrontier
Deal found 12/29$351
This United Airlines deal was found by Cheapflights users on 12/28. 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.
Mon 12/294:35 pmMTJ - ONT
1 stop7h 06mUnited Airlines
Mon 1/55:05 amONT - MTJ
1 stop6h 33mUnited Airlines
Deal found 12/28$424
This United Airlines deal was found by Cheapflights users on 12/28. 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.
Mon 12/293:12 pmGJT - ONT
1 stop6h 55mUnited Airlines
Mon 1/55:05 amONT - GJT
1 stop6h 33mUnited Airlines
Deal found 12/28$429

Find flight deals from Colorado to Ontario

Keep the following information in mind while searching for Colorado to Ontario flight deals. Data was last updated December 30, 2025.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$88
(Frontier)

One-way from

$42
(Super.com)

Popular in

June

Cheapest in

February

Average price

$211

Good round-trip deal

$155 or less

Good one-way deal

$64 or less
Provider with most accurate pricing for Denver Intl-Los Angeles flight deals.
Search Deals
Provider most trusted by Cheapflights users for Denver Intl-Los Angeles flights.
Search Deals
From Colorado to Ontario
Search Deals
One-way flight from Colorado to Ontario
Search Deals
Highest demand for flights based on searches. 8% potential increase in price ($17 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($4 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
Search Deals
Price to beat on a round-trip flight from Colorado to Ontario.
Search Deals
Price to beat on a one-way flight from Colorado to Ontario.
Search Deals

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 December 30, 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

Tue 2/3

1:34 pm-3:07 pm

Nonstop2h 33m

Ontario

Sat 2/7

7:35 pm-12:41 pm

1 stop16h 06m

$130

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 1/27

11:49 am-5:03 pm

1 stop6h 14m

Ontario

Sat 1/31

4:03 pm-11:35 pm

1 stop6h 32m

$176

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 1/27

11:49 am-5:03 pm

1 stop6h 14m

Ontario

Tue 2/3

4:03 pm-11:35 pm

1 stop6h 32m

$176

DenverOntario

DEN - ONT

DENONT

Denver Intl

Mon 2/2

5:09 pm-11:56 pm

1 stop7h 47m

Ontario

Wed 2/4

4:03 pm-11:35 pm

1 stop6h 32m

$194

DenverOntario

DEN - ONT

DENONT

Denver Intl

Mon 2/2

5:09 pm-11:56 pm

1 stop7h 47m

Ontario

Wed 2/11

11:53 am-11:35 pm

1 stop10h 42m

$194

DenverOntario

DEN - ONT

DENONT

Denver Intl

Fri 1/30

11:49 am-5:03 pm

1 stop6h 14m

Ontario

Sat 1/31

4:03 pm-11:35 pm

1 stop6h 32m

$196

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Tue 1/20

7:59 am-12:16 pm

1 stop5h 17m

Ontario

Tue 1/27

6:00 am-11:17 am

1 stop4h 17m

$197

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Wed 1/28

3:21 pm-8:58 pm

1 stop6h 37m

Ontario

Wed 2/4

1:24 pm-8:38 pm

1 stop6h 14m

$211

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Wed 2/25

6:53 pm-10:19 pm

1 stop4h 26m

Ontario

Sun 3/1

6:15 am-11:32 am

1 stop4h 17m

$211

DenverOntario

DEN - ONT

DENONT

Denver Intl

Thu 1/22

11:49 am-5:03 pm

1 stop6h 14m

Ontario

Sat 1/24

4:03 pm-11:35 pm

1 stop6h 32m

$212

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/27

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, February is the cheapest month in which you can book a flight from Colorado to Ontario (average of $38). 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 December 30, 2025.

It’s optimal to fly from Colorado to Ontario in the evening. By choosing this option you can save up to 16% on the cost of your flight, compared to a flight at noon.

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 27, 2025.

Travelers seeking maximum savings on their Colorado to Ontario flight should consider departing on Wednesday 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 December 30, 2025.

The most flights from USCO to ONT are scheduled on a Monday (10 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (3 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 58 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 $130, Frontier can have you in Ontario from Colorado in 2h 33m. 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 Frontier ($38), United Airlines ($78), and Southwest ($78).

  • 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 Volaris (100%), Air Canada (95%) or United Airlines (92%) 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 $206, our data shows the cheapest flight currently is $29. 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, February is the cheapest month in which you can book a flight from Colorado to Ontario (average of $38). 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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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 December 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$63Average$159FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$120Average$314FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$132Average$369FlexibilityNo cancel feeOn-time69%
DeltaCheapest$196Average$283FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$218Average$346FlexibilityNo cancel feeOn-time71%

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