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$78+ Cheap flights from Ontario (ONT) to Colorado

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 9/1. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
1 adult, Economy
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Cheap flight deals from Ontario to Colorado

Keep the following information in mind while searching for Ontario to Colorado flight deals. Data was last updated June 12, 2025.

Round-trip from

$119
(Cheapflightsfares)

One-way from

$78
(Kiwi.com)

Popular in

June

Cheapest in

January

Average price

$223

Good round-trip deal

$198 or less

Good one-way deal

$108 or less
From Ontario to Colorado
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One-way flight from Ontario to Colorado
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Highest demand for flights based on searches. 9% potential increase in price ($18 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 June 2025
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Price to beat on a round-trip flight from Ontario to Colorado.
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Price to beat on a one-way flight from Ontario to Colorado.
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Find flight deals from Ontario to Colorado

Cheapest flights from Ontario to Colorado
Explore the most affordable flight options available from Ontario to Colorado. Find the lowest fares from popular airlines and budget airlines, with prices last updated on June 12, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 6/12. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/712:59 amONT - DEN
Nonstop2h 20mFrontier
Mon 8/1110:29 pmDEN - ONT
Nonstop2h 21mFrontier
Deal found 6/12$119
This United Airlines deal was found by Cheapflights users on 6/11. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/205:10 amONT - DEN
Nonstop2h 17mUnited Airlines
Tue 8/267:25 pmDEN - ONT
Nonstop2h 18mUnited Airlines
Deal found 6/11$157
This Southwest deal was found by Cheapflights users on 6/11. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/206:05 amONT - DEN
2 stops7h 00mSouthwest
Mon 8/258:30 amDEN - ONT
Nonstop2h 15mSouthwest
Deal found 6/11$172
This Delta deal was found by Cheapflights users on 6/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/229:44 amONT - DEN
1 stop4h 16mDelta
Wed 7/236:10 pmDEN - ONT
1 stop6h 32mDelta
Deal found 6/11$217
This American Airlines deal was found by Cheapflights users on 6/11. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/124:45 pmONT - DEN
1 stop3h 57mAmerican Airlines
Mon 7/146:45 pmDEN - ONT
1 stop3h 53mAmerican Airlines
Deal found 6/11$218
This Delta deal was found by Cheapflights users on 6/10. 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.
Fri 7/41:15 pmONT - GJT
1 stop4h 02mDelta
Fri 7/116:50 pmGJT - ONT
1 stop5h 52mDelta
Deal found 6/10$229
This United Airlines deal was found by Cheapflights users on 6/9. 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 7/145:05 amONT - GJT
1 stop6h 42mUnited Airlines
Thu 7/241:45 pmGJT - ONT
2 stops10h 07mUnited Airlines
Deal found 6/9$234
This Delta deal was found by Cheapflights users on 6/11. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/105:09 pmONT - COS
1 stop4h 04mDelta
Fri 7/118:15 amCOS - ONT
1 stop4h 59mDelta
Deal found 6/11$273
This United Airlines deal was found by Cheapflights users on 6/11. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/105:05 amONT - COS
1 stop7h 09mUnited Airlines
Fri 7/116:00 amCOS - ONT
2 stops7h 14mUnited Airlines
Deal found 6/11$294
This United Airlines deal was found by Cheapflights users on 6/11. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/305:10 amONT - ASE
1 stop4h 40mUnited Airlines
Sat 9/68:45 amASE - ONT
1 stop4h 47mUnited Airlines
Deal found 6/11$299
This United Airlines deal was found by Cheapflights users on 6/10. 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.
Tue 7/295:05 amONT - MTJ
1 stop6h 43mUnited Airlines
Sat 8/23:30 pmMTJ - ONT
1 stop6h 24mUnited Airlines
Deal found 6/10$304
This American Airlines deal was found by Cheapflights users on 6/11. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 7/2112:59 amONT - COS
1 stop7h 52mAmerican Airlines
Sat 8/26:01 amCOS - ONT
1 stop6h 55mAmerican Airlines
Deal found 6/11$312

Cheapflights Fare Finder

Customize your flight search to find flights from Ontario to Colorado 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 June 12, 2025.
Use the filters below to find and compare flights from Ontario to Colorado that are best for you.

Fly from

Ontario

Fly to

Colorado

Route

Depart

Return

Price

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 8/9

12:59 am-4:19 am

Nonstop2h 20m

Denver Intl

Mon 8/11

7:53 am-9:13 am

Nonstop2h 20m

$119

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 8/20

5:10 am-8:27 am

Nonstop2h 17m

Denver Intl

Tue 8/26

7:25 pm-8:43 pm

Nonstop2h 18m

$157

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 8/20

2:45 pm-6:00 pm

Nonstop2h 15m

Denver Intl

Tue 8/26

10:45 am-5:35 pm

2 stops7h 50m

$172

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 7/22

9:44 am-3:00 pm

1 stop4h 16m

Denver Intl

Wed 7/23

6:10 pm-11:42 pm

1 stop6h 32m

$217

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 7/12

4:45 pm-9:42 pm

1 stop3h 57m

Denver Intl

Mon 7/14

6:45 pm-9:38 pm

1 stop3h 53m

$218

OntarioGrand Junction

ONT - GJT

ONTGJT

Ontario

Fri 7/4

1:15 pm-6:17 pm

1 stop4h 02m

Grand Junction Regnl

Fri 7/11

6:50 pm-11:42 pm

1 stop5h 52m

$229

OntarioGrand Junction

ONT - GJT

ONTGJT

Ontario

Mon 7/14

5:05 am-12:47 pm

1 stop6h 42m

Grand Junction Regnl

Thu 7/24

1:45 pm-10:52 pm

2 stops10h 07m

$234

OntarioColorado Springs

ONT - COS

ONTCOS

Ontario

Thu 7/10

5:09 pm-10:13 pm

1 stop4h 04m

Colorado Springs

Fri 7/11

8:15 am-12:14 pm

1 stop4h 59m

$273

OntarioColorado Springs

ONT - COS

ONTCOS

Ontario

Thu 7/10

5:05 am-1:14 pm

1 stop7h 09m

Colorado Springs

Fri 7/11

6:00 am-12:14 pm

2 stops7h 14m

$294

OntarioAspen

ONT - ASE

ONTASE

Ontario

Sat 8/30

5:10 am-10:50 am

1 stop4h 40m

Aspen Pitkin County

Sat 9/6

8:45 am-12:32 pm

1 stop4h 47m

$299

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/12

Showing 1-10 of 46 results
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Best time to book a flight from Ontario to Colorado

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

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

Currently, October is the cheapest month in which you can book a flight from Ontario to Colorado (average of $197). Flying from Ontario to Colorado in March is currently the most expensive (average of $278). 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 ONT to CO?

Find hourly flight availability from Ontario to Colorado. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated June 12, 2025.

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

Weekly flight availability from Ontario to Colorado

Explore weekly flight availability from Ontario to Colorado. 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 June 12, 2025.

The most flights from ONT to USCO are scheduled on a Thursday (12 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (4 on average).

Rainfall in Colorado by month

Plan your trip to Colorado by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Colorado ranges from 0.5 - 2.3 inches per month. May is typically the wettest month, when rainfall can reach 2.3 in. January is typically the driest time to visit Colorado when rainfall is around 0.5 in.

Temperature in Colorado by month

Plan your trip to Colorado by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Colorado, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

Reviews of airlines servicing Colorado

Get insights into the airlines that provide service to Colorado. 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 Colorado. Reviews last updated June 12, 2025.
Get a feel of what it's like to fly with Alaska Airlines, Southwest and Delta from Ontario to Colorado by reading reviews from past customers. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,287 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,950 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.9
Good
2,494 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Boarding

8.1

Entertainment

7.1

Overall

8.0

Comfort

7.8

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Related info for your journey

Find useful and relevant information for your journey from Ontario to Colorado. 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 from for flights from Ontario to Colorado?

    Ontario (ONT), located 3.1 mi from the city center, is the airport you fly out of when you book flights from Ontario to Colorado.

  • How popular is this Ontario to Colorado flight route?

    The Ontario to Colorado flight path was viewed by 339 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

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

    The cheapest airlines for a one-way flight from Ontario to Colorado are Frontier ($78), United Airlines ($79), and Alaska Airlines ($88).

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

    The most popular route from Ontario to Colorado is Ontario - Denver Intl. You may also consider Ontario - Colorado Springs or Ontario - Montrose County.

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

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Ontario to Colorado on time: SkyWest Airlines (83%), United Airlines (73%), Southwest (70%).

  • What are the cheapest flights from Ontario to Colorado?

    Looking at all options, your cheapest flight can be booked for $67. While the most popular route (Ontario - Denver Intl) can be booked for $125 on average our data indicates $922 when flying from Ontario to Colorado.

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

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

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

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

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

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

    Currently, October is the cheapest month in which you can book a flight from Ontario to Colorado (average of $197). Flying from Ontario to Colorado in March is currently the most expensive (average of $278). 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 Ontario to Colorado

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Top 5 airlines flying from Ontario to Colorado

Discover the top 5 airlines that operate flights from Ontario to Colorado. 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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$54Average$127FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$103Average$342FlexibilityNo cancel feeOn-time63%
DeltaCheapest$109Average$311FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$130Average$395FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$288Average$392FlexibilityNo cancel feeOn-time71%

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