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$44+ 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 2/20. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
Feb 13 — Feb 201
Fri 2/13
Fri 2/20
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 January 14, 2026.

Most accurate provider

CheapOair
3 stars

Most trusted provider

CheapOair
3 stars

Round-trip from

$67
(Super.com)

One-way from

$44
(Expedia)

Popular in

June

Cheapest in

September

Average price

$177

Good round-trip deal

$216 or less

Good one-way deal

$133 or less
Provider with most accurate pricing for Los Angeles-Denver Intl flight deals.
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Provider most trusted by Cheapflights users for Los Angeles-Denver Intl flights.
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From Ontario to Colorado
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One-way flight from Ontario to Colorado
Search Deals
Highest demand for flights based on searches. 7% potential increase in price ($15 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 January 2026
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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 January 14, 2026.

This Super.com deal was found by Cheapflights users on 1/13. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 2/226:10 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Fri 2/2710:29 pm
DEN
-
ONT
Nonstop2h 30m
Frontier
Deal found 1/13$67
This Frontier deal was found by Cheapflights users on 1/12. 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.
Sun 3/16:10 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Tue 3/1010:29 pm
DEN
-
ONT
Nonstop2h 30m
Frontier
Deal found 1/12$69
This CheapOair deal was found by Cheapflights users on 1/12. 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.
Thu 2/126:05 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Sat 2/1410:29 pm
DEN
-
ONT
Nonstop2h 30m
Frontier
Deal found 1/12$70
This Frontier deal was found by Cheapflights users on 1/12. 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 3/56:05 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Tue 3/1010:29 pm
DEN
-
ONT
Nonstop2h 30m
Frontier
Deal found 1/12$71
This Kiwi.com deal was found by Cheapflights users on 1/13. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 2/206:00 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Wed 2/258:00 pm
DEN
-
ONT
Nonstop2h 34m
Frontier
Deal found 1/13$72
This Frontier deal was found by Cheapflights users on 1/12. 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 3/66:15 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Sat 3/710:29 pm
DEN
-
ONT
Nonstop2h 30m
Frontier
Deal found 1/12$73
This Frontier deal was found by Cheapflights users on 1/12. 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.
Sun 2/156:10 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Tue 2/178:00 pm
DEN
-
ONT
Nonstop2h 34m
Frontier
Deal found 1/12$74
This Frontier deal was found by Cheapflights users on 1/13. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 2/286:00 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Wed 3/48:00 pm
DEN
-
ONT
Nonstop2h 34m
Frontier
Deal found 1/13$75
This Frontier deal was found by Cheapflights users on 1/13. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 2/286:00 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Sat 3/710:29 pm
DEN
-
ONT
Nonstop2h 30m
Frontier
Deal found 1/13$76
This Super.com deal was found by Cheapflights users on 1/13. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 2/156:10 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Fri 2/2010:29 pm
DEN
-
ONT
Nonstop2h 30m
Frontier
Deal found 1/13$77
This Frontier deal was found by Cheapflights users on 1/13. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 3/16:10 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Fri 3/610:29 pm
DEN
-
ONT
Nonstop2h 30m
Frontier
Deal found 1/13$78
This Super.com deal was found by Cheapflights users on 1/12. 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.
Thu 2/196:05 am
ONT
-
DEN
Nonstop2h 20m
Frontier
Sun 2/226:20 am
DEN
-
ONT
Nonstop2h 39m
Frontier
Deal found 1/12$79

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 January 14, 2026.
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

Wed 3/25

6:15 am-9:35 am

Nonstop2h 20m

Denver Intl

Sat 3/28

10:29 pm-11:59 pm

Nonstop2h 30m

$89

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 1/27

3:07 pm-10:32 am

1 stop18h 25m

Denver Intl

Wed 1/28

5:11 pm-10:32 am

1 stop18h 21m

$160

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 3/3

3:20 pm-9:25 pm

1 stop5h 05m

Denver Intl

Wed 3/4

8:35 am-2:40 pm

2 stops7h 05m

$182

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 3/24

4:35 pm-11:15 pm

1 stop5h 40m

Denver Intl

Sat 3/28

5:35 am-9:50 am

1 stop5h 15m

$195

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 3/26

6:30 pm-12:40 am

1 stop5h 10m

Denver Intl

Wed 4/1

6:15 am-9:40 am

1 stop4h 25m

$195

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 2/11

6:00 am-11:51 am

1 stop4h 51m

Denver Intl

Wed 2/11

6:23 pm-11:58 pm

1 stop6h 35m

$197

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 2/14

5:45 am-10:25 am

1 stop3h 40m

Denver Intl

Tue 2/17

5:25 pm-10:05 pm

2 stops5h 40m

$200

OntarioColorado Springs

ONT - COS

ONTCOS

Ontario

Tue 2/3

5:05 am-10:57 am

1 stop4h 52m

Colorado Springs

Sat 2/7

8:40 am-12:47 pm

1 stop5h 07m

$205

OntarioColorado Springs

ONT - COS

ONTCOS

Ontario

Tue 2/3

5:10 pm-10:23 pm

1 stop4h 13m

Colorado Springs

Sat 2/7

12:03 pm-10:44 pm

2 stops11h 41m

$210

OntarioMontrose

ONT - MTJ

ONTMTJ

Ontario

Wed 1/28

5:05 am-12:30 pm

1 stop6h 25m

Montrose County

Sun 2/1

4:07 pm-10:53 pm

1 stop7h 46m

$211

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/13

Showing 1-10 of 60 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, March is the cheapest month in which you can book a flight from Ontario to Colorado (average of $36). Flying from Ontario to Colorado in September is currently the most expensive (average of $75). 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 January 14, 2026.

It’s typically best to fly out from Ontario to Colorado in the evening. Doing so could potentially save you 54% on the flight price compared to flying at noon, which is usually more expensive.

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

Use this chart to determine the cheapest time to fly round-trip from Ontario to Colorado. Price data was last updated on January 10, 2026.

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

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 January 14, 2026.

The most flights from ONT to USCO are scheduled on a Tuesday (8 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (2 on average).

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 January 14, 2026.
See what other customers who have flown with Southwest, Delta, and United Airlines from Ontario to Colorado have to say. 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.
Southwest
8.0
Very good
4,257 reviews

Entertainment

7.5

Crew

8.6

Boarding

8.1

Food

7.0

Comfort

8.0

Overall

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
Southwest
8.0
Very good
4,257 reviews
Southwest
8.0
Very good
4,257 reviews

Entertainment

7.5

Crew

8.6

Boarding

8.1

Food

7.0

Comfort

8.0

Overall

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
Delta
7.9
Good
8,040 reviews
Southwest
8.0
Very good
4,257 reviews

Entertainment

7.5

Crew

8.6

Boarding

8.1

Food

7.0

Comfort

8.0

Overall

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
United Airlines
7.4
Good
9,156 reviews
Southwest
8.0
Very good
4,257 reviews

Entertainment

7.5

Crew

8.6

Boarding

8.1

Food

7.0

Comfort

8.0

Overall

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
American Airlines
7.2
Good
11,118 reviews
Southwest
8.0
Very good
4,257 reviews

Entertainment

7.5

Crew

8.6

Boarding

8.1

Food

7.0

Comfort

8.0

Overall

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am
Frontier
5.7
Fair
3,056 reviews
Southwest
8.0
Very good
4,257 reviews

Entertainment

7.5

Crew

8.6

Boarding

8.1

Food

7.0

Comfort

8.0

Overall

8.0

Reviews

1 / 20
2.0
Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

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 340 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 Ontario to Colorado?

    Airlines like Frontier, Southwest, and United Airlines fly from Ontario to Colorado in about 2h 20m. The time it takes to get you to your destination can typically vary by up to 2h 45m. The distance from Ontario to Colorado is about 817 mi. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

  • 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 ($36), Southwest ($68), and United Airlines ($78).

  • 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 - Aspen Pitkin County or Ontario - Colorado Springs.

  • 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: Volaris (85%), Frontier (85%), Southwest (77%).

  • What are the cheapest flights from Ontario to Colorado?

    Looking at all options, your cheapest flight can be booked for $72. While the most popular route (Ontario - Denver Intl) can be booked for $58 on average, our data indicates $750 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, March is the cheapest month in which you can book a flight from Ontario to Colorado (average of $36). Flying from Ontario to Colorado in September is currently the most expensive (average of $75). 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.

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Alternative routes for Ontario to Colorado

See prices for flight routes from nearby airports that may be better suited for you.
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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 January 14, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$60Average$148FlexibilityNo cancel feeOn-time62%
DeltaCheapest$109Average$265FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$117Average$313FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$141Average$349FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$268Average$383FlexibilityNo cancel feeOn-time71%

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