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Ontario

$36+ 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 7/21. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ONT
Jun 28 — Jul 51
Sun 6/28
Sun 7/5
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 May 29, 2026.

This Frontier deal was found by Cheapflights users on 5/27. 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 10/712:32 pm
DEN
-
ONT
Nonstop2h 25m
Frontier
Tue 10/276:15 am
ONT
-
DEN
Nonstop2h 26m
Frontier
Deal found 5/27$66
This Kiwi.com deal was found by Cheapflights users on 5/27. 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 10/610:34 pm
DEN
-
ONT
Nonstop2h 21m
Frontier
Wed 10/282:35 pm
ONT
-
DEN
Nonstop2h 22m
Frontier
Deal found 5/27$67
This Cheapflightsfares deal was found by Cheapflights users on 5/27. 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.
Wed 7/18:44 am
DEN
-
ONT
Nonstop2h 21m
Frontier
Tue 7/146:00 am
ONT
-
DEN
Nonstop2h 24m
Frontier
Deal found 5/27$74
This Frontier deal was found by Cheapflights users on 5/27. 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.
Tue 10/610:34 pm
DEN
-
ONT
Nonstop2h 21m
Frontier
Mon 10/262:55 pm
ONT
-
DEN
Nonstop2h 22m
Frontier
Deal found 5/27$87
This Cheapflightsfares deal was found by Cheapflights users on 5/28. 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.
Thu 9/1010:34 pm
DEN
-
ONT
Nonstop2h 21m
Frontier
Tue 9/156:00 am
ONT
-
DEN
Nonstop2h 26m
Frontier
Deal found 5/28$91
This Kiwi.com deal was found by Cheapflights users on 5/24. 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 6/308:44 am
DEN
-
ONT
Nonstop2h 21m
Frontier
Tue 7/76:00 am
ONT
-
DEN
Nonstop2h 24m
Frontier
Deal found 5/24$95
This Frontier deal was found by Cheapflights users on 5/24. 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.
Tue 6/308:44 am
DEN
-
ONT
Nonstop2h 21m
Frontier
Wed 7/86:00 am
ONT
-
DEN
Nonstop2h 24m
Frontier
Deal found 5/24$96
This Frontier deal was found by Cheapflights users on 5/24. 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 6/248:44 am
DEN
-
ONT
Nonstop2h 21m
Frontier
Wed 7/16:00 am
ONT
-
DEN
Nonstop2h 26m
Frontier
Deal found 5/24$97
This Cheapflightsfares deal was found by Cheapflights users on 5/26. 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 7/288:45 am
DEN
-
ONT
Nonstop2h 19m
Frontier
Tue 8/410:49 am
ONT
-
DEN
Nonstop2h 21m
Frontier
Deal found 5/26$99
This Frontier deal was found by Cheapflights users on 5/27. 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.
Tue 7/218:45 am
DEN
-
ONT
Nonstop2h 19m
Frontier
Tue 8/116:00 am
ONT
-
DEN
Nonstop2h 24m
Frontier
Deal found 5/27$101
This Frontier deal was found by Cheapflights users on 5/28. 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 9/910:34 pm
DEN
-
ONT
Nonstop2h 21m
Frontier
Mon 9/212:55 pm
ONT
-
DEN
Nonstop2h 22m
Frontier
Deal found 5/28$102
This Frontier deal was found by Cheapflights users on 5/24. 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.
Sat 9/1910:34 pm
DEN
-
ONT
Nonstop2h 21m
Frontier
Tue 9/226:00 am
ONT
-
DEN
Nonstop2h 26m
Frontier
Deal found 5/24$103

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 May 29, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$74
(Cheapflightsfares)

One-way from

$36
(Kiwi.com)

Popular in

March

Cheapest in

February

Average price

$207

Good round-trip deal

$152 or less

Good one-way deal

$94 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. 7% potential increase in price ($16 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($5 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in May 2026
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 May 29, 2026.
Use the filters below to find and compare flights from Colorado to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 6/30

6:15 am-9:15 am

1 stop4h 00m

Ontario

Tue 7/7

7:20 pm-12:20 am

1 stop4h 00m

$165

DenverOntario

DEN - ONT

DENONT

Denver Intl

Mon 8/17

6:17 pm-11:34 pm

1 stop6h 17m

Ontario

Tue 8/18

12:55 pm-8:01 pm

1 stop6h 06m

$197

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 7/21

7:05 am-12:10 pm

1 stop6h 05m

Ontario

Wed 7/22

6:00 am-11:47 am

1 stop4h 47m

$197

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 8/18

7:05 am-12:05 pm

1 stop6h 00m

Ontario

Wed 9/9

1:00 pm-7:10 pm

1 stop5h 10m

$197

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Sat 8/15

8:10 am-12:05 pm

1 stop4h 55m

Ontario

Tue 8/25

9:43 am-5:36 pm

1 stop6h 53m

$197

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 7/14

8:45 am-10:04 am

Nonstop2h 19m

Ontario

Thu 7/16

11:52 am-9:41 pm

1 stop8h 49m

$238

DenverOntario

DEN - ONT

DENONT

Denver Intl

Wed 8/5

3:10 pm-8:55 pm

1 stop6h 45m

Ontario

Wed 8/19

2:10 pm-9:20 pm

2 stops6h 10m

$266

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Mon 6/15

6:55 pm-9:57 pm

1 stop4h 02m

Ontario

Sat 6/20

6:10 am-11:35 am

1 stop4h 25m

$271

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Sat 9/5

7:41 am-12:05 pm

1 stop5h 24m

Ontario

Mon 9/14

5:13 pm-9:50 pm

1 stop3h 37m

$271

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Sat 8/8

7:41 am-12:05 pm

1 stop5h 24m

Ontario

Wed 8/12

5:05 pm-9:56 pm

1 stop3h 51m

$271

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/28

Showing 1-10 of 60 resultsSorted by cheapest first
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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, November is the cheapest month in which you can book a flight from Colorado to Ontario (average of $44). Flying from Colorado to Ontario in June is currently the most expensive (average of $88). 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 May 29, 2026.

It’s optimal to fly from Colorado to Ontario in the evening. By choosing this option you can save up to 22% on the cost of your flight, compared to a flight at noon.

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 May 29, 2026.

The most flights from USCO to ONT are scheduled on a Thursday (16 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (6 on average).

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

How far ahead should I book a flight from Colorado to Ontario?

To ensure you get the cheapest price possible for a flight from Colorado to Ontario, you should look to book at least 82 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

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 May 23, 2026.

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 afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

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 66 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 $238, Southwest can have you in Ontario from Colorado in 2h 19m. 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 ($39), United Airlines ($74), and Southwest ($88).

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

    While some choose either Grand Junction Regnl - Ontario or Colorado Springs - 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 (91%), Volaris (91%) or Air Canada (91%) 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 $174, our data shows the cheapest flight currently is $28. When looking at the most popular route, (Denver Intl - Ontario), you can expect to pay $129 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, November is the cheapest month in which you can book a flight from Colorado to Ontario (average of $44). Flying from Colorado to Ontario in June is currently the most expensive (average of $88). 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 May 29, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$65Average$175FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$131Average$384FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$157Average$322FlexibilityNo cancel feeOn-time63%
DeltaCheapest$196Average$288FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$200Average$349FlexibilityNo cancel feeOn-time71%

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