HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Ontario

$56+ 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 9/10. Fares are subject to change and may not be available on all flights or dates of travel.
DEN — ONT
Aug 5 — Aug 121
Tue 8/5
Tue 8/12
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Colorado to Ontario with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

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 July 31, 2025.

Round-trip from

$99
(Gotogate)

One-way from

$57
(FlightHub)

Popular in

June

Cheapest in

September

Average price

$208

Good round-trip deal

$142 or less

Good one-way deal

$99 or less
From Colorado to Ontario
Search Deals
One-way flight from Colorado to Ontario
Search Deals
Highest demand for flights based on searches. 10% potential increase in price ($22 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($4 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 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

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 July 31, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 7/29. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/2410:29 pmDEN - ONT
Nonstop2h 21mFrontier
Mon 10/276:11 pmONT - DEN
Nonstop2h 22mFrontier
Deal found 7/29$81
This American Airlines deal was found by Cheapflights users on 7/29. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/214:37 pmASE - ONT
1 stop6h 37mAmerican Airlines
Sun 8/246:10 amONT - ASE
1 stop6h 47mAmerican Airlines
Deal found 7/29$228
This Southwest deal was found by Cheapflights users on 7/31. 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 8/305:00 pmCOS - ONT
1 stop4h 40mSouthwest
Mon 9/13:30 pmONT - COS
1 stop6h 05mSouthwest
Deal found 7/31$237
This American Airlines deal was found by Cheapflights users on 7/30. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/206:27 amCOS - ONT
1 stop6h 25mAmerican Airlines
Sun 8/2412:22 pmONT - COS
2 stops10h 22mAmerican Airlines
Deal found 7/30$242
This United Airlines deal was found by Cheapflights users on 7/31. 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 10/2312:54 pmCOS - ONT
1 stop5h 29mUnited Airlines
Mon 10/275:05 amONT - COS
1 stop7h 09mUnited Airlines
Deal found 7/31$249
This Delta deal was found by Cheapflights users on 7/30. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/208:00 amCOS - ONT
1 stop5h 14mDelta
Sun 8/244:50 pmONT - COS
1 stop4h 28mDelta
Deal found 7/30$271
This United Airlines deal was found by Cheapflights users on 7/30. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/63:21 pmGJT - ONT
1 stop6h 33mUnited Airlines
Wed 8/135:05 amONT - GJT
1 stop6h 31mUnited Airlines
Deal found 7/30$279
This American Airlines deal was found by Cheapflights users on 7/29. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/152:09 pmGJT - ONT
1 stop5h 11mAmerican Airlines
Sun 11/164:47 pmONT - GJT
1 stop4h 30mAmerican Airlines
Deal found 7/29$295
This American Airlines deal was found by Cheapflights users on 7/29. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/208:15 amEGE - ONT
1 stop6h 24mAmerican Airlines
Sun 8/2410:50 amONT - EGE
1 stop6h 54mAmerican Airlines
Deal found 7/29$299
This United Airlines deal was found by Cheapflights users on 7/30. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/67:08 amASE - ONT
1 stop6h 05mUnited Airlines
Sat 10/115:05 amONT - ASE
1 stop4h 34mUnited Airlines
Deal found 7/30$299
This Delta deal was found by Cheapflights users on 7/30. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/66:00 amGJT - ONT
1 stop3h 47mDelta
Mon 8/111:15 pmONT - GJT
1 stop4h 00mDelta
Deal found 7/30$309
This United Airlines deal was found by Cheapflights users on 7/31. 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 8/281:40 pmEGE - ONT
1 stop4h 49mUnited Airlines
Sun 8/311:15 pmONT - EGE
1 stop5h 57mUnited Airlines
Deal found 7/31$337

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 July 31, 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

Fri 10/24

10:29 pm-11:50 pm

Nonstop2h 21m

Ontario

Mon 10/27

6:11 pm-9:33 pm

Nonstop2h 22m

$81

AspenOntario

ASE - ONT

ASEONT

Aspen Pitkin County

Thu 8/21

4:37 pm-10:14 pm

1 stop6h 37m

Ontario

Sun 8/24

6:10 am-1:57 pm

1 stop6h 47m

$228

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Sat 8/30

5:00 pm-8:40 pm

1 stop4h 40m

Ontario

Mon 9/1

3:30 pm-10:35 pm

1 stop6h 05m

$237

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Wed 8/20

6:27 am-11:52 am

1 stop6h 25m

Ontario

Sun 8/24

12:22 pm-11:44 pm

2 stops10h 22m

$242

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Thu 10/23

12:54 pm-5:23 pm

1 stop5h 29m

Ontario

Mon 10/27

5:05 am-1:14 pm

1 stop7h 09m

$249

Colorado SpringsOntario

COS - ONT

COSONT

Colorado Springs

Wed 8/20

8:00 am-12:14 pm

1 stop5h 14m

Ontario

Sun 8/24

4:50 pm-10:18 pm

1 stop4h 28m

$271

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Sat 11/15

2:09 pm-6:20 pm

1 stop5h 11m

Ontario

Sun 11/16

4:47 pm-10:17 pm

1 stop4h 30m

$295

AspenOntario

ASE - ONT

ASEONT

Aspen Pitkin County

Sat 9/6

7:08 am-12:13 pm

1 stop6h 05m

Ontario

Sat 10/11

5:05 am-10:39 am

1 stop4h 34m

$299

Grand JunctionOntario

GJT - ONT

GJTONT

Grand Junction Regnl

Sat 8/23

3:19 pm-8:43 pm

1 stop6h 24m

Ontario

Sun 8/31

5:10 am-12:36 pm

1 stop6h 26m

$299

VailOntario

EGE - ONT

EGEONT

Vail Eagle County

Wed 8/20

8:15 am-1:39 pm

1 stop6h 24m

Ontario

Sat 8/23

6:10 am-1:58 pm

1 stop6h 48m

$299

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/29

Showing 1-10 of 32 results
1
2
3
4

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 July 31, 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 July 31, 2025.

The most flights from USCO to ONT are scheduled on a Monday (12 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (6 on average).

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 July 31, 2025.
Read reviews from past customers who have flown Alaska Airlines, Southwest, and Delta from Colorado to Ontario. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Food

7.1

Overall

8.0

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

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Food

7.1

Overall

8.0

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
4,246 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Food

7.1

Overall

8.0

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
7,981 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Food

7.1

Overall

8.0

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
7.8
Good
2,611 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Food

7.1

Overall

8.0

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
8,900 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Comfort

7.8

Boarding

8.1

Food

7.1

Overall

8.0

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 65 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 ($57), Southwest ($79), and Alaska Airlines ($88).

  • 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 (100%), United Airlines (72%) or Frontier (70%) 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 $168, our data shows the cheapest flight currently is $54. When looking at the most popular route, (Denver Intl - Ontario), you can expect to pay $110 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

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Colorado to Ontario

See prices for flight routes from nearby airports that may be better suited for you.
John F Kennedy Intl to Los Angeles flights
John F Kennedy Intl to Las Vegas flights
Dallas/Fort Worth to Las Vegas flights
Newark to Los Angeles flights
Los Angeles to Las Vegas flights
John F Kennedy Intl to San Francisco flights
Dallas/Fort Worth to Los Angeles flights
Newark to San Francisco flights
Los Angeles to San Jose flights
Hobby to Las Vegas flights
Los Angeles to San Francisco flights
O'Hare Intl to Las Vegas flights
Newark to Las Vegas flights
Ontario to San Francisco flights
Denver to Las Vegas flights
LaGuardia to Los Angeles flights
Santa Ana to Las Vegas flights
LaGuardia to Las Vegas flights
Burbank to Las Vegas flights
Santa Ana to San Francisco flights
San Francisco to Los Angeles flights
Seattle to Los Angeles flights
Seattle to Las Vegas flights
San Jose to Los Angeles flights
Dulles Intl to Las Vegas flights
Boston to Las Vegas flights
Seattle to San Francisco flights
San Francisco to Ontario flights
San Francisco to Santa Ana flights
George Bush Intcntl to Las Vegas flights
San Francisco to Las Vegas flights
Seattle to San Diego flights
Baltimore to Las Vegas flights
Boston to Los Angeles flights
Oakland to Los Angeles flights
Dallas/Fort Worth to San Francisco flights
LaGuardia to San Francisco flights
O'Hare Intl to Los Angeles flights
San Jose to Las Vegas flights
Reagan-National to Los Angeles flights
Atlanta to Las Vegas flights
John F Kennedy Intl to Ontario flights
Fort Lauderdale to Las Vegas flights
O'Hare Intl to San Francisco flights
Santa Ana to Oakland flights
Oakland to Las Vegas flights
Newark to Burbank flights
Newark to San Diego flights
John F Kennedy Intl to San Diego flights
Dulles Intl to Los Angeles flights

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 July 31, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$58Average$146FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$120Average$321FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$148Average$365FlexibilityNo cancel feeOn-time69%
DeltaCheapest$256Average$288FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$278Average$351FlexibilityNo cancel feeOn-time71%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.