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$71+ 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 9/22. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ONT
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
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 June 12, 2025.

Round-trip from

$116
(Cheapflightsfares)

One-way from

$71
(Kiwi.com)

Popular in

June

Cheapest in

September

Average price

$223

Good round-trip deal

$139 or less

Good one-way deal

$94 or less
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. 9% potential increase in price ($18 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 June 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 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 8/217:25 amDEN - ONT
Nonstop2h 20mFrontier
Sun 8/2412:59 amONT - DEN
Nonstop2h 20mFrontier
Deal found 6/12$116
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/202:45 pmDEN - ONT
Nonstop2h 20mSouthwest
Fri 9/263:15 pmONT - DEN
1 stop6h 20mSouthwest
Deal found 6/12$187
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/295:45 amDEN - ONT
1 stop4h 10mDelta
Fri 9/56:05 amONT - DEN
1 stop4h 46mDelta
Deal found 6/9$217
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.
Mon 8/45:55 pmCOS - ONT
1 stop6h 47mDelta
Mon 8/119:50 amONT - COS
1 stop6h 25mDelta
Deal found 6/11$218
This Delta 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/46:52 pmGJT - ONT
1 stop4h 53mDelta
Tue 7/81:15 pmONT - GJT
1 stop4h 00mDelta
Deal found 6/12$229
This American 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/206:02 amCOS - ONT
1 stop8h 37mAmerican Airlines
Sun 8/2412:22 pmONT - COS
2 stops10h 22mAmerican Airlines
Deal found 6/10$250
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 11/911:50 amMTJ - ONT
1 stop8h 50mSouthwest
Tue 11/185:45 amONT - MTJ
1 stop4h 35mSouthwest
Deal found 6/10$258
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.
Sat 7/1211:15 amDEN - ONT
Nonstop2h 17mUnited Airlines
Mon 7/145:05 amONT - DEN
Nonstop2h 18mUnited Airlines
Deal found 6/10$268
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/106:35 pmCOS - ONT
1 stop6h 20mSouthwest
Thu 7/175:25 pmONT - COS
1 stop3h 55mSouthwest
Deal found 6/10$273
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.
Wed 7/235:30 amCOS - ONT
2 stops7h 44mUnited Airlines
Sun 7/276:28 pmONT - COS
1 stop4h 24mUnited Airlines
Deal found 6/10$278
This United Airlines 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/208:45 amASE - ONT
1 stop4h 47mUnited Airlines
Tue 9/235:10 amONT - ASE
1 stop4h 40mUnited Airlines
Deal found 6/12$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.
Sat 11/157:00 amGJT - ONT
1 stop6h 33mUnited Airlines
Sun 11/235:40 amONT - GJT
1 stop4h 04mUnited Airlines
Deal found 6/10$299

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 June 12, 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

Thu 8/21

7:25 am-8:45 am

Nonstop2h 20m

Ontario

Sun 8/24

12:59 am-4:19 am

Nonstop2h 20m

$116

DenverOntario

DEN - ONT

DENONT

Denver Intl

Thu 8/21

9:50 am-12:40 pm

1 stop3h 50m

Ontario

Mon 8/25

5:20 am-10:00 am

1 stop3h 40m

$172

DenverOntario

DEN - ONT

DENONT

Denver Intl

Fri 8/29

5:45 am-8:55 am

1 stop4h 10m

Ontario

Fri 9/5

6:05 am-11:51 am

1 stop4h 46m

$217

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Mon 8/4

5:55 pm-11:42 pm

1 stop6h 47m

Ontario

Mon 8/11

9:50 am-5:15 pm

1 stop6h 25m

$218

DenverOntario

DEN - ONT

DENONT

Denver Intl

Thu 8/7

4:05 pm-5:25 pm

Nonstop2h 20m

Ontario

Mon 8/11

1:34 pm-4:52 pm

Nonstop2h 18m

$228

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Fri 7/4

6:52 pm-10:45 pm

1 stop4h 53m

Ontario

Tue 7/8

1:15 pm-6:15 pm

1 stop4h 00m

$229

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Wed 8/20

6:02 am-1:39 pm

1 stop8h 37m

Ontario

Sun 8/24

12:22 pm-11:44 pm

2 stops10h 22m

$250

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Thu 7/10

6:35 pm-11:55 pm

1 stop6h 20m

Ontario

Thu 7/17

5:25 pm-10:20 pm

1 stop3h 55m

$273

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Wed 7/23

5:30 am-12:14 pm

2 stops7h 44m

Ontario

Sun 7/27

6:28 pm-11:52 pm

1 stop4h 24m

$278

AspenOntario

ASE - ONT

ASEONT

Aspen Pitkin County

Sat 9/20

8:45 am-12:32 pm

1 stop4h 47m

Ontario

Tue 9/23

5:10 am-10:50 am

1 stop4h 40m

$299

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/10

Showing 1-10 of 30 results
1
2
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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, August is the cheapest month in which you can book a flight from Colorado to Ontario (average of $246). Flying from Colorado to Ontario in March is currently the most expensive (average of $328). 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 June 12, 2025.

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

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 June 12, 2025.

The most flights from USCO to ONT are scheduled on a Wednesday (11 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 Ontario by month

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

In terms of precipitation, rainfall in Ontario ranges from 0.1 - 3.4 inches per month. February is typically the wettest month, when rainfall can reach 3.4 in. June is typically the driest time to visit Ontario when rainfall is around 0.1 in.

Temperature in Ontario by month

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

If weather is an important factor for your trip to Ontario, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 78.8 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 53.6 F).

Reviews of airlines servicing Ontario

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

Food

7.1

Entertainment

7.1

Boarding

8.1

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

Entertainment

7.1

Boarding

8.1

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

Entertainment

7.1

Boarding

8.1

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
7,946 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Food

7.1

Entertainment

7.1

Boarding

8.1

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

Entertainment

7.1

Boarding

8.1

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

Entertainment

7.1

Boarding

8.1

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 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 70 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 Colorado to Ontario one-way?

    The cheapest airlines for a one-way flight from Colorado to Ontario are Frontier ($71), Southwest ($84), and Hawaiian Airlines ($86).

  • 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 SkyWest Airlines (83%), Frontier (81%) or United Airlines (78%) 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 $171, our data shows the cheapest flight currently is $49. 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, August is the cheapest month in which you can book a flight from Colorado to Ontario (average of $246). Flying from Colorado to Ontario in March is currently the most expensive (average of $328). 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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$56Average$132FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$117Average$326FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$137Average$385FlexibilityNo cancel feeOn-time69%
DeltaCheapest$256Average$288FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$278Average$363FlexibilityNo cancel feeOn-time71%

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