How many flights depart from Ontario to Denver on average per day?

The number of flights available between Ontario and Denver is 10 per day as of August 2026. The most frequent departure time is 6:00AM, with 48% of daily flights leaving at noon.

What airlines fly to Denver?

Frontier, United Airlines and Southwest are the top three most popular airlines that fly to Denver from Ontario according to our data. Frontier is the first choice among our users, with 48% of people opting to fly with this airline when traveling to Denver. Keep in mind that there are 8 different airlines that fly to Denver on a routine basis, so you have a few additional options to choose from.

How many flights depart from Ontario to Denver on average per week?

As of August 2026, 73 flights take off from Ontario and land in Denver each week. The most common flight departure day for this route is Mon, with 19% of weekly flights taking off on this day.

What is the cheapest airline that flies from Ontario to Denver Intl?

United Airlines and Delta are the most popular carriers operating from Ontario to Denver Intl

When did momondo last update prices for flights from Ontario Airport to Denver Intl Airport?

Prices for flights from Ontario Airport to Denver Intl Airport were last updated today.

How many operators does momondo search for flights from Ontario Airport to Denver Intl Airport?

The number of operators available for flights from Ontario Airport to Denver Intl Airport is 4 as of August 2026.

How old do you have to be to fly from Ontario Airport to Denver Intl Airport?

The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Ontario Airport to Denver Intl Airport.

What documentation or ID do you need to fly to Denver Intl Airport?

The travel and health documents required for your trip to Denver Intl Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Denver Intl Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

$23 Cheap Flights from Ontario to Denver in 2026

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from Ontario to Denver

Round-trip

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Enter your travel dates to find the best prices.

6:45 pm - 12:10 pmONT Ontario-DEN Denver Intl

16h 25m1 stop Houston George Bush Intcntl

10:29 pm - 11:47 pmDEN Denver Intl-ONT Ontario

2h 18mnonstop

$108Frontier

Thu, Oct 1 - Mon, Oct 5

11:45 am - 3:07 pmONT Ontario-DEN Denver Intl

2h 22mnonstop

6:38 pm - 9:09 amDEN Denver Intl-ONT Ontario

15h 31m1 stop Las Vegas Harry Reid Intl

$109Frontier

Thu, Sep 10 - Mon, Sep 14

6:40 am - 1:50 pmONT Ontario-DEN Denver Intl

6h 10m1 stop Phoenix Sky Harbor Intl

7:30 pm - 8:55 pmDEN Denver Intl-ONT Ontario

2h 25mnonstop

$167Southwest

Wed, Sep 9 - Sat, Sep 12

12:40 pm - 3:50 pmONT Ontario-DEN Denver Intl

2h 10mnonstop

8:55 pm - 10:15 pmDEN Denver Intl-ONT Ontario

2h 20mnonstop

$177Southwest

Thu, Oct 1 - Mon, Oct 5

5:00 am - 8:11 amONT Ontario-DEN Denver Intl

2h 11mnonstop

7:05 pm - 8:20 pmDEN Denver Intl-ONT Ontario

2h 15mnonstop

$177United Airlines

Wed, Dec 16 - Wed, Jan 6

1:23 pm - 7:22 pmONT Ontario-DEN Denver Intl

4h 59m1 stop Phoenix Sky Harbor Intl

6:56 pm - 10:01 pmDEN Denver Intl-ONT Ontario

4h 05m1 stop Phoenix Sky Harbor Intl

$177American Airlines

Wed, Dec 16 - Wed, Jan 6

12:57 pm - 6:06 pmONT Ontario-DEN Denver Intl

4h 09m1 stop Phoenix Sky Harbor Intl

11:43 am - 4:07 pmDEN Denver Intl-ONT Ontario

5h 24m1 stop Phoenix Sky Harbor Intl

$177American Airlines

Thu, Jan 7 - Mon, Jan 11

5:00 am - 8:11 amONT Ontario-DEN Denver Intl

2h 11mnonstop

1:25 pm - 5:47 pmDEN Denver Intl-ONT Ontario

5h 22m1 stop San Francisco

$187United Airlines

Wed, Dec 16 - Wed, Jan 6

5:11 pm - 11:00 pmONT Ontario-DEN Denver Intl

4h 49m1 stop Salt Lake City

6:10 pm - 11:58 pmDEN Denver Intl-ONT Ontario

6h 48m1 stop Salt Lake City

$197Delta

Wed, Nov 18 - Mon, Dec 7

5:11 pm - 11:00 pmONT Ontario-DEN Denver Intl

4h 49m1 stop Salt Lake City

7:50 am - 12:10 pmDEN Denver Intl-ONT Ontario

5h 20m1 stop Salt Lake City

$197Delta

Wed, Nov 18 - Wed, Dec 2

Cheap last minute flights

Enter your travel dates to find the best prices.

3:40 pm - 12:10 amONT Ontario-DEN Denver Intl

7h 30m1 stop Las Vegas Harry Reid Intl

10:29 pm - 11:47 pmDEN Denver Intl-ONT Ontario

2h 18mnonstop

$245Frontier

Fri, Aug 21 - Mon, Sep 21

3:40 pm - 6:00 pmONT Ontario-DEN Denver Intl

25h 20m1 stop Las Vegas Harry Reid Intl

8:45 am - 10:04 amDEN Denver Intl-ONT Ontario

2h 19mnonstop

$250Frontier

Fri, Aug 21 - Mon, Aug 31

5:00 am - 8:21 amONT Ontario-DEN Denver Intl

2h 21mnonstop

7:30 pm - 8:53 pmDEN Denver Intl-ONT Ontario

2h 23mnonstop

$463United Airlines

Fri, Aug 21 - Mon, Sep 21

1:56 pm - 8:07 pmONT Ontario-DEN Denver Intl

5h 11m1 stop San Francisco

7:30 pm - 8:53 pmDEN Denver Intl-ONT Ontario

2h 23mnonstop

$473United Airlines

Fri, Aug 21 - Mon, Sep 21

6:02 am - 2:02 pmONT Ontario-DEN Denver Intl

7h 00m1 stop Seattle/Tacoma Intl

10:29 pm - 11:50 pmDEN Denver Intl-ONT Ontario

2h 21mnonstop

$512Multiple Airlines

Fri, Aug 21 - Wed, Aug 26

5:45 pm - 11:45 pmONT Ontario-DEN Denver Intl

5h 00m1 stop Las Vegas Harry Reid Intl

12:55 pm - 6:20 pmDEN Denver Intl-ONT Ontario

6h 25m2 stops San Diego San Jose

$524Southwest

Thu, Aug 20 - Sat, Aug 29

10:47 am - 6:32 pmONT Ontario-DEN Denver Intl

6h 45m1 stop Portland

10:29 pm - 11:50 pmDEN Denver Intl-ONT Ontario

2h 21mnonstop

$540Multiple Airlines

Fri, Aug 21 - Mon, Aug 24

8:35 am - 4:05 pmONT Ontario-DEN Denver Intl

6h 30m2 stops San Jose Las Vegas Harry Reid Intl

10:15 am - 3:05 pmDEN Denver Intl-ONT Ontario

5h 50m2 stops Tucson Phoenix Sky Harbor Intl

$577Southwest

Sat, Aug 22 - Thu, Aug 27

6:00 am - 11:47 amONT Ontario-DEN Denver Intl

4h 47m1 stop Salt Lake City

6:28 pm - 10:23 pmDEN Denver Intl-ONT Ontario

4h 55m1 stop Salt Lake City

$669Delta

Sat, Aug 22 - Sat, Aug 22

9:43 am - 3:02 pmONT Ontario-DEN Denver Intl

4h 19m1 stop Salt Lake City

5:35 am - 8:52 amDEN Denver Intl-ONT Ontario

4h 17m1 stop Salt Lake City

$669Delta

Fri, Aug 21 - Wed, Aug 26

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Frontier flights from Ontario to Denver

Our best Frontier deals on Ontario to Denver flight tickets

Frontier

Oct 1

ONT6:45 pmOntario

16h 25m

1 stop

DEN12:10 pmDenver Intl

Oct 5

DEN10:29 pmDenver Intl

2h 18m

ONT11:47 pmOntario

$108

Frontier

Sep 10

ONT11:45 amOntario

2h 22m

DEN3:07 pmDenver Intl

Sep 14

DEN6:38 pmDenver Intl

15h 31m

1 stop

ONT9:09 amOntario

$109

Frontier

Sep 2

ONT6:00 amOntario

2h 24m

DEN9:24 amDenver Intl

Sep 5

DEN10:29 pmDenver Intl

2h 21m

ONT11:50 pmOntario

$110

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 10/1

6:45 pm-12:10 pm

1 stop16h 25m

Denver Intl

Mon 10/5

10:29 pm-11:47 pm

Nonstop2h 18m

$108

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 9/10

11:45 am-3:07 pm

Nonstop2h 22m

Denver Intl

Mon 9/14

6:38 pm-9:09 am

1 stop15h 31m

$109

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Wed 9/9

6:40 am-1:50 pm

1 stop6h 10m

Denver Intl

Sat 9/12

7:30 pm-8:55 pm

Nonstop2h 25m

$167

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 10/1

12:40 pm-3:50 pm

Nonstop2h 10m

Denver Intl

Mon 10/5

8:55 pm-10:15 pm

Nonstop2h 20m

$177

Quickest round-trip

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Wed 12/16

5:00 am-8:11 am

Nonstop2h 11m

Denver Intl

Wed 1/6

7:05 pm-8:20 pm

Nonstop2h 15m

$177

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Wed 12/16

1:23 pm-7:22 pm

1 stop4h 59m

Denver Intl

Wed 1/6

6:56 pm-10:01 pm

1 stop4h 05m

$177

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 1/7

12:57 pm-6:06 pm

1 stop4h 09m

Denver Intl

Mon 1/11

11:43 am-4:07 pm

1 stop5h 24m

$177

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Wed 12/16

5:00 am-8:11 am

Nonstop2h 11m

Denver Intl

Wed 1/6

1:25 pm-5:47 pm

1 stop5h 22m

$187

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Wed 11/18

5:11 pm-11:00 pm

1 stop4h 49m

Denver Intl

Mon 12/7

6:10 pm-11:58 pm

1 stop6h 48m

$197

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Wed 11/18

5:11 pm-11:00 pm

1 stop4h 49m

Denver Intl

Wed 12/2

7:50 am-12:10 pm

1 stop5h 20m

$197

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first

How to get the cheapest flight ticket from Ontario to Denver

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

Prices

Airlines

Other information

What is the typical price of a round-trip flight between Ontario and Denver?

Prices are currently low for flights on this route.

Typical prices usually range from $161 to $315.
The lowest price recently found on this route was $108.

What is the cheapest month to fly to Denver?

The cheapest month to fly to Denver from Ontario is in February. Flight prices, which tend to average around $164, are often lower during this time because this is during the off-season. If you don’t want to visit Denver in February, then you should wait until January to fly from Ontario, when ticket prices are also cheap, with an average price of $168.

What is the cheapest day to depart on your flight to Denver?

The cheapest day to depart on your flight to Denver is on a Wednesday when prices can be found for as low as $288. This is often the case because there is less demand to fly during this day of the week. The most expensive day to fly to Denver is Sunday, with ticket prices averaging around $376.

What is the cheapest time of day to depart on your flight to Denver?

The cheapest time of day to fly to Denver is in the evening when flights can be purchased for as low as $270. Flights in the morning are often more expensive with an average ticket price of $321.

What is the cheapest Ontario to Denver Intl flight route?

Fly from Ontario to Denver Intl for the best Ontario - Denver Intl flight prices

How far in advance should I book a flight from Ontario to Denver?

You are more likely to see cheaper flights to Denver from Ontario when booking weeks ahead of your departure date. In general, you can expect to find flights to Denver for around $223 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Denver from Ontario for as low as $162 on momondo.

What cabin class options are available on Ontario to Denver flights?

There are 4 cabin classes available to choose from on Ontario to Denver flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

How have Ontario to Denver flight prices changed over time?

As of August 2026, prices for Ontario to Denver flights are approximately 11% cheaper when compared to flights at the same time last year.

When to book flights from Ontario to Denver

Are you open to changing your travel dates? Check out the ideal times to fly from Ontario to Denver according to our flight data. Find out which month and days have the cheapest flights.

Estimated round-trip price

Cheap Ontario to Denver (ONT to DEN) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Ontario to Denver

Best Price Found	$23
Fastest flight time	2h 11m
Direct flights	Tue, Wed, Thu, Fri, Sat and Sun
Airports in Denver	1 airport

The best one-way flight to Denver from Ontario in the past 72 hours is $23. The best round-trip flight deal from Ontario to Denver found on momondo in the last 72 hours is $108.

The fastest flight from Ontario to Denver takes 2h 11m

Direct flights go from Ontario to Denver on Tuesday, Wednesday, Thursday, Friday, Saturday and Sunday. The only airline offering direct flights is United Airlines.

There is 1 airport in Denver. From Ontario there are direct flights to Denver Intl (DEN).

Search flight deals

Frequently asked questions about flying from Ontario to Denver

How far is Ontario to Denver Intl by plane?
The straight-line distance from Ontario to Denver Intl is 800.5 mi. A reasonable flight in good conditions will take 2h 11m.
When did momondo last update prices for flights from Ontario Airport to Denver Intl Airport?
Prices for flights from Ontario Airport to Denver Intl Airport were last updated today.
How many operators does momondo search for flights from Ontario Airport to Denver Intl Airport?
The number of operators available for flights from Ontario Airport to Denver Intl Airport is 4 as of August 2026.
How old do you have to be to fly from Ontario Airport to Denver Intl Airport?
The minimum age for a child to fly alone is five, but airlines offering an unaccompanied minor (UNMR) service may have their age restrictions, such as regulations concerning flight duration, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Ontario Airport to Denver Intl Airport.
What documentation or ID do you need to fly to Denver Intl Airport?
The travel and health documents required for your trip to Denver Intl Airport can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Denver Intl Airport. We always recommend checking with your airline or a trusted third party such as IATA to get advice.
What is the most popular plane model from Ontario to Denver?
Based on momondo bookings for flights between Ontario and Denver, the leading plane model is Airbus A320neo, making up 13.49% of the total bookings. Other popular models include Boeing 737 MAX 8 with 10.76%, Airbus A321-100/200 with 8.55%, and Boeing 737-800 with 8.35%.
What is the most popular airline from Ontario to Denver?
Based on momondo bookings for this flight route, the most popular airline on flight routes from Ontario to Denver is Frontier (71% of total bookings). The next most popular airlines are Southwest (17%), United Airlines (11%), and Delta (0%).

Best airlines flying from Ontario to Denver

Compare and see reviews for airlines that fly from Ontario to Denver with momondo

Airline	Rating	Free Cancellation	Price
Frontier	PriceFrom $61	Free Cancellation	Rating 5.6 2,678 reviews	Search Frontier flights
Delta	PriceFrom $98	Free Cancellation	Rating 7.8 8,503 reviews	Search Delta flights
Southwest	PriceFrom $157	Free Cancellation	Rating 8.0 4,217 reviews	Search Southwest flights
United Airlines	PriceFrom $157	Free Cancellation	Rating 7.4 10,107 reviews	Search United Airlines flights

Southwest Flights From Ontario to Denver
Southwest flies from Ontario to Denver around 26 times per week, with 4,217 momondo users rating the airline 8.0/10. The cheapest Southwest deal from Ontario to Denver in the last 72 hours was $157 (round-trip), much lower than the average airfare cost of $330 for Southwest flights on this route.
United Airlines Flights From Ontario to Denver
Another popular option for Ontario to Denver flights is United Airlines (7.4/10, 10,107 ratings). United Airlines flies from Ontario to Denver around 14 times per week, with deals starting from $157 round-trip and rising to an average price of around $292.

Breckenridge

Estes Park

Black Hawk

Aurora

Fort Collins

Boulder

Westminster

Longmont

Manitou Springs

Lakewood

Greeley

Keystone

Thornton

Cripple Creek

Centennial

Littleton

Englewood

Frisco

Winter Park

Golden

Why use momondo?

Why should I use momondo to find a flight deal from Ontario to Denver?

Finding the right flight to Denver from Ontario is quick and easy when you have a range of options in front of you, from reputable agents and recognisable airlines. Options that can then be filtered down to find the best fit. That is what momondo does. We make finding flights to Denver quick and easy, saving you time and money.

Can I find flights from Ontario to Denver with flexible booking policies on momondo?

Yes. momondo allows you to filter the results for Ontario to Denver flights to just show those with flexible booking policies.

How can momondo help me find flights from Ontario to Denver?

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from Ontario to Denver.

I’m not ready to book a flight from Ontario to Denver right now. Can momondo alert me if prices change?

If you are simply researching potential flights to Denver, momondo offers a useful price alert feature which will track prices for flights to Denver from Ontario and alert you when they change.

An easier way to manage your Denver trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

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Airports servicing Colorado

Alamosa Airport

Aspen Pitkin County Airport

Cortez Montezuma County Airport

Colorado Springs Airport

Durango La Plata County Airport

Vail Eagle County Airport

Grand Junction Regnl Airport

Gunnison Airport

Hayden Yampa Valley Airport

Montrose County Airport

Telluride Airport

Cheap flights from Ontario to Denver from $23

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Ontario to Denver departing on 9/22. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.

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Frontier flights from Ontario to Denver

Our best Frontier deals on Ontario to Denver flight tickets

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Use the filters below to find and compare flights from Ontario to Denver that are best for you.

See travel insights to Denver from

How to get the cheapest flight ticket from Ontario to Denver

What is the typical price of a round-trip flight between Ontario and Denver?

What is the cheapest month to fly to Denver?

What is the cheapest day to depart on your flight to Denver?

What is the cheapest time of day to depart on your flight to Denver?

What is the cheapest Ontario to Denver Intl flight route?

How far in advance should I book a flight from Ontario to Denver?

What cabin class options are available on Ontario to Denver flights?

How have Ontario to Denver flight prices changed over time?

What is the cheapest airline that flies from Ontario to Denver Intl?

What airlines fly to Denver?

How many flights depart from Ontario to Denver on average per day?

How many flights depart from Ontario to Denver on average per week?

When to book flights from Ontario to Denver

Cheap Ontario to Denver (ONT to DEN) flight deals and tips

Best Price Found

Fastest flight time

Direct flights

Airports in Denver

Frequently asked questions about flying from Ontario to Denver

Best airlines flying from Ontario to Denver

Compare and see reviews for airlines that fly from Ontario to Denver with momondo

Traveling to a place near Denver?

Why use momondo?

An easier way to manage your Denver trip

We make it super easy to schedule, organize and travel with friends or family. Trips is free — and available to use no matter where you book.

Get notified when prices go down

Daily price changes in your inbox - only with Price Alerts.

Find better results for your trip to the United States

Airports servicing Colorado

Fly your favorite airline to Denver

Airlines are sorted and displayed according to clicks in the past 7 days on momondo

Cabin classes currently available on flights to Denver

List of cabin classes available on flights landing in Denver. Availability may vary depending on flight origin and airline.

Popular cities in the United States

Popular flights according to clicks in the last 7 days on momondo

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