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

As of September 2026, 80 flights take off from Ontario and land in Denver each week. The most common flight departure day for this route is Fri, with 19% of weekly flights taking off on this day.

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

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

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

The number of flights available between Ontario and Denver is 11 per day as of September 2026. The most frequent departure time is 6:00, with 50% of daily flights leaving at midday.

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 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 stopovers. 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 required travel and health documents for your Denver Intl Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's licence and a passport valid for six months after your intended arrival at Denver Intl Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.

R1 273 Cheap Flights from Ontario to Denver in 2026

Find the cheapest flights from Ontario to Denver

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One-way

Last minute

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Cheap return flights

Enter your travel dates to find the best prices.

10:56 - 21:09ONT Ontario-DEN Denver Intl

9h 13m1 stop Portland

14:55 - 20:02DEN Denver Intl-ONT Ontario

6h 07m1 stop Portland

R2 852Alaska Airlines

Thu, Jan 7 - Mon, Jan 11

16:15 - 21:00ONT Ontario-DEN Denver Intl

3h 45m1 stop Phoenix Sky Harbor Intl

14:45 - 19:50DEN Denver Intl-ONT Ontario

6h 05m2 stops Tucson Phoenix Sky Harbor Intl

R2 868Southwest

Mon, Oct 26 - Tue, Oct 27

18:55 - 0:50ONT Ontario-DEN Denver Intl

4h 55m1 stop Phoenix Sky Harbor Intl

5:45 - 11:10DEN Denver Intl-ONT Ontario

6h 25m2 stops Las Vegas Harry Reid Intl Phoenix Sky Harbor Intl

R2 933Southwest

Mon, Oct 19 - Sat, Oct 24

5:00 - 8:21ONT Ontario-DEN Denver Intl

2h 21mdirect

19:25 - 20:51DEN Denver Intl-ONT Ontario

2h 26mdirect

R3 013United Airlines

Sat, Oct 24 - Mon, Oct 26

13:35 - 19:34ONT Ontario-DEN Denver Intl

4h 59m1 stop Salt Lake City

5:25 - 8:55DEN Denver Intl-ONT Ontario

4h 30m1 stop Salt Lake City

R3 174Delta

Sat, Oct 10 - Mon, Oct 12

7:10 - 14:07ONT Ontario-DEN Denver Intl

5h 57m1 stop Portland

14:55 - 20:02DEN Denver Intl-ONT Ontario

6h 07m1 stop Portland

R3 464Alaska Airlines

Fri, Jan 8 - Mon, Jan 11

5:35 - 12:50ONT Ontario-DEN Denver Intl

6h 15m2 stops Las Vegas Harry Reid Intl Tucson

14:10 - 18:45DEN Denver Intl-ONT Ontario

5h 35m1 stop Las Vegas Harry Reid Intl

R3 545Southwest

Fri, Nov 6 - Sat, Nov 7

17:04 - 23:09ONT Ontario-DEN Denver Intl

5h 05m1 stop Salt Lake City

12:53 - 16:24DEN Denver Intl-ONT Ontario

4h 31m1 stop Salt Lake City

R3 625Delta

Fri, Nov 13 - Wed, Nov 18

13:00 - 16:14ONT Ontario-DEN Denver Intl

2h 14mdirect

19:05 - 20:20DEN Denver Intl-ONT Ontario

2h 15mdirect

R3 738United Airlines

Sat, Jan 9 - Sat, Jan 9

5:00 - 8:11ONT Ontario-DEN Denver Intl

2h 11mdirect

19:05 - 20:20DEN Denver Intl-ONT Ontario

2h 15mdirect

R3 819United Airlines

Wed, Jan 6 - Sat, Jan 9

Cheap last-minute flights

Enter your travel dates to find the best prices.

8:35 - 16:20ONT Ontario-DEN Denver Intl

6h 45m1 stop San Jose

9:10 - 15:15DEN Denver Intl-ONT Ontario

7h 05m2 stops Fresno Airterminal Las Vegas Harry Reid Intl

R9 539Southwest

Sat, Sep 19 - Sat, Sep 26

11:00 - 17:55ONT Ontario-DEN Denver Intl

5h 55m2 stops Las Vegas Harry Reid Intl Phoenix Sky Harbor Intl

10:15 - 15:05DEN Denver Intl-ONT Ontario

5h 50m2 stops Tucson Phoenix Sky Harbor Intl

R9 620Southwest

Sat, Sep 19 - Thu, Sep 24

13:18 - 16:39ONT Ontario-DEN Denver Intl

2h 21mdirect

11:30 - 12:50DEN Denver Intl-ONT Ontario

2h 20mdirect

R10 780United Airlines

Fri, Sep 18 - Sun, Sep 20

5:00 - 8:21ONT Ontario-DEN Denver Intl

2h 21mdirect

15:50 - 20:01DEN Denver Intl-ONT Ontario

5h 11m1 stop San Francisco

R10 941United Airlines

Sat, Sep 19 - Sun, Sep 20

6:08 - 12:36ONT Ontario-DEN Denver Intl

5h 28m1 stop San Francisco

15:50 - 20:01DEN Denver Intl-ONT Ontario

5h 11m1 stop San Francisco

R11 005United Airlines

Sat, Sep 19 - Sat, Sep 19

6:08 - 12:36ONT Ontario-DEN Denver Intl

5h 28m1 stop San Francisco

6:00 - 12:12DEN Denver Intl-ONT Ontario

7h 12m1 stop San Francisco

R11 102United Airlines

Fri, Sep 18 - Mon, Sep 21

10:35 - 21:30ONT Ontario-DEN Denver Intl

9h 55m2 stops Sacramento Intl Seattle/Tacoma Intl

16:15 - 19:35DEN Denver Intl-ONT Ontario

4h 20m1 stop Las Vegas Harry Reid Intl

R11 183Southwest

Sat, Sep 19 - Sun, Sep 20

6:30 - 14:30ONT Ontario-DEN Denver Intl

7h 00m2 stops Oakland Portland

11:15 - 19:50DEN Denver Intl-ONT Ontario

9h 35m2 stops Seattle/Tacoma Intl Oakland

R11 199Southwest

Fri, Sep 18 - Sat, Sep 19

8:35 - 17:35ONT Ontario-DEN Denver Intl

8h 00m2 stops San Jose Portland

10:15 - 15:05DEN Denver Intl-ONT Ontario

5h 50m2 stops Tucson Phoenix Sky Harbor Intl

R11 263Southwest

Sat, Sep 19 - Thu, Sep 24

16:27 - 12:20ONT Ontario-DEN Denver Intl

18h 53m2 stops Santa Rosa Sonoma County San Diego

11:50 - 17:18DEN Denver Intl-ONT Ontario

6h 28m1 stop Portland

R12 391Alaska Airlines

Thu, Sep 17 - Sun, Sep 20

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United Airlines flights from Ontario to Denver

Our best United Airlines deals on Ontario to Denver flight tickets

United Airlines

Oct 24

ONT5:00Ontario

2h 21m

DEN8:21Denver Intl

Oct 26

DEN19:25Denver Intl

2h 26m

ONT20:51Ontario

R3 013

United Airlines

Jan 9

ONT13:00Ontario

2h 14m

DEN16:14Denver Intl

Jan 9

DEN19:05Denver Intl

2h 15m

ONT20:20Ontario

R3 738

United Airlines

Jan 6

ONT5:00Ontario

2h 11m

DEN8:11Denver Intl

Jan 9

DEN19:05Denver Intl

2h 15m

ONT20:20Ontario

R3 819

Alaska Airlines flights from Ontario to Denver

Our best Alaska Airlines deals on Ontario to Denver flight tickets

Alaska Airlines

Jan 7

ONT10:56Ontario

9h 13m

1 stop

DEN21:09Denver Intl

Jan 11

DEN14:55Denver Intl

6h 07m

1 stop

ONT20:02Ontario

R2 852

Alaska Airlines

Jan 8

ONT7:10Ontario

5h 57m

1 stop

DEN14:07Denver Intl

Jan 13

DEN14:55Denver Intl

6h 07m

1 stop

ONT20:02Ontario

R3 464

Alaska Airlines

Jan 7

ONT7:00Ontario

13h 09m

2 stops

DEN21:09Denver Intl

Jan 11

DEN14:55Denver Intl

6h 07m

1 stop

ONT20:02Ontario

R4 673

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 7/1

10:56-21:09

1 stop9h 13m

Denver Intl

Mon 11/1

14:55-20:02

1 stop6h 07m

R2 852

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Mon 26/10

16:15-21:00

1 stop3h 45m

Denver Intl

Tue 27/10

14:45-19:50

2 stops6h 05m

R2 868

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Mon 19/10

18:55-0:50

1 stop4h 55m

Denver Intl

Sat 24/10

5:45-11:10

2 stops6h 25m

R2 933

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Sat 24/10

5:00-8:21

Nonstop2h 21m

Denver Intl

Mon 26/10

19:25-20:51

Nonstop2h 26m

R3 013

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Sat 10/10

13:35-19:34

1 stop4h 59m

Denver Intl

Mon 12/10

5:25-8:55

1 stop4h 30m

R3 174

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Fri 8/1

7:10-14:07

1 stop5h 57m

Denver Intl

Mon 11/1

14:55-20:02

1 stop6h 07m

R3 464

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Fri 6/11

5:35-12:50

2 stops6h 15m

Denver Intl

Sat 7/11

14:10-18:45

1 stop5h 35m

R3 545

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Fri 13/11

17:04-23:09

1 stop5h 05m

Denver Intl

Wed 18/11

12:53-16:24

1 stop4h 31m

R3 625

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Sat 9/1

13:00-16:14

Nonstop2h 14m

Denver Intl

Sat 9/1

19:05-20:20

Nonstop2h 15m

R3 738

Fastest return journey

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Wed 6/1

5:00-8:11

Nonstop2h 11m

Denver Intl

Sat 9/1

19:05-20:20

Nonstop2h 15m

R3 819

Flights are sorted by cheapest return 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 typical for flights on this route.

Typical prices usually range from R2 739 to R5 624.
The lowest price recently found on this route was R2 852.

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 R2 643, 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 R2 707.

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 R3 750 when searching weeks before you fly. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Denver from Ontario for as low as R3 013 on momondo.

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

There is only 1 cabin class 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 September 2026, prices for Ontario to Denver flights are approximately 21% 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 return 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	R1 273
Direct flights	Every day
Airports in Denver	1 airport

The best one-way flight to Denver from Ontario in the past 72 hours is R1 273. The best return flight deal from Ontario to Denver found on momondo in the last 72 hours is R2 852.

Direct flights go from Ontario to Denver every day.

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?
Ontario and Denver Intl are 1288,3 km apart from one another.
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 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 stopovers. 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 required travel and health documents for your Denver Intl Airport trip may vary depending on your itinerary and personal circumstances. As a general rule, you should carry multiple documents, including a national ID card or driver's licence and a passport valid for six months after your intended arrival at Denver Intl Airport. We recommend that you seek guidance from your airline or a reliable third party such as IATA.
What is the most popular plane model from Ontario to Denver?
Based on momondo bookings for this flight route, the most popular plane model on flight routes from Ontario to Denver is Airbus A320neo (12,71% of total bookings). The next most popular plane models are Boeing 737 MAX 8 (10,71%), Airbus A321neo (9,64%), and Boeing 737-800 (8,13%).

Estes Park

Black Hawk

Manitou Springs

Why use momondo?

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

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from Ontario to Denver. momondo saves you time and could save you money on your trip.

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

momondo does allow users to show only those flights to Denver from Ontario which offer a flexible booking policy as well as other useful filters and features.

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

Once you have performed a search in the form on the page, momondo provides useful filters and insights. We can show you the cheapest days and times to fly as well as help filter your options to help you make an informed choice when booking flights to Denver from Ontario.

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

Price alerts on flights to Denver from Ontario are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.