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ONT - DEN

Find cheap flights from Ontario to Denver from $37

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Ontario to Denver departing on 5/17. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
0 bags
Sat 5/25
Sat 6/1

Search hundreds of travel sites at once for deals on flights to Denver

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to Denver, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to Denver, as well as popular online travel agencies
In the last 7 days travelers have searched 44,979,812 times on KAYAK, and here is why:

Save 22% or moreCompare multiple travel sites with one search.

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Cheap flight deals from Ontario to Denver (ONT-DEN)

Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Ontario to Denver that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices and deals for you by selecting your travel dates.
Choose your dates
12:59 am - 4:23 amONT-DEN
2h 24mnonstop
5:01 am - 6:26 amDEN-ONT
2h 25mnonstop
$53Frontier
Find Deal
Mon, May 6 - Wed, May 15
12:59 am - 4:23 amONT-DEN
2h 24mnonstop
5:01 am - 6:26 amDEN-ONT
2h 25mnonstop
$58Frontier
Find Deal
Mon, May 13 - Wed, May 15
12:55 am - 4:19 amONT-DEN
2h 24mnonstop
10:35 pm - 11:59 pmDEN-ONT
2h 24mnonstop
$59Frontier
Find Deal
Fri, May 10 - Tue, May 14
12:59 am - 4:23 amONT-DEN
2h 24mnonstop
5:01 am - 6:26 amDEN-ONT
2h 25mnonstop
$62Frontier
Find Deal
Mon, May 6 - Wed, May 8
7:16 am - 10:36 amONT-DEN
2h 20mnonstop
5:01 am - 6:26 amDEN-ONT
2h 25mnonstop
$66Frontier
Find Deal
Tue, May 7 - Tue, May 14
12:59 am - 4:23 amONT-DEN
2h 24mnonstop
5:01 am - 6:26 amDEN-ONT
2h 25mnonstop
$67Frontier
Find Deal
Tue, May 7 - Sat, May 11
12:59 am - 4:20 amONT-DEN
2h 21mnonstop
10:37 pm - 11:59 pmDEN-ONT
2h 22mnonstop
$68Frontier
Find Deal
Tue, May 21 - Tue, May 28
7:16 am - 10:36 amONT-DEN
2h 20mnonstop
5:01 am - 6:26 amDEN-ONT
2h 25mnonstop
$69Frontier
Find Deal
Tue, May 7 - Wed, May 8
1:20 pm - 7:16 pmONT-DEN
4h 56m1 stop
6:10 pm - 11:43 pmDEN-ONT
6h 33m1 stop
$196Delta
Find Deal
Sat, May 25 - Tue, May 28
12:53 pm - 6:13 pmONT-DEN
4h 20m1 stop
6:53 pm - 10:29 pmDEN-ONT
4h 36m1 stop
$208American Airlines
Find Deal
Thu, May 30 - Sat, Jun 1

Flights from Ontario to Denver - Travel Insights & Trends

Get data-powered insights and trends into flights from Ontario to Denver to help you find the cheapest flights, the best time to fly and much more.

What’s the cheapest day of the week to fly from Ontario to Denver?

The average price of all flights from Ontario to Denver clicked on KAYAK for each day over the last 12 months.
If you are looking for a flight deal from Ontario to Denver, look for departures on Tuesdays and avoid leaving on a Monday, as it's usually the priciest day. When flying back from Denver, Tuesday is the cheapest day to fly and Sunday is the most expensive.

What is the cheapest month to fly from Ontario to Denver?

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for flights from Ontario to Denver, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.
The cheapest month for flights from Ontario to Denver is January, where tickets cost $163 on average. On the other hand, the most expensive months are June and July, where the average cost of tickets is $298 and $268 respectively.

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

To calculate daily average prices, KAYAK takes all prices for each day before departure over the last year for flights from Ontario to Denver, removes the top 0.1% to account for outliers, and then takes the average of all the values for each month.
To get a below average price on the flight from Ontario to Denver, you should book around 2 weeks before departure. For the absolute cheapest price, our data suggests you should book 28 days before departure.

Which airlines provide the cheapest flights from Ontario to Denver?

The cheapest price for the route for each airline clicked by KAYAK users in the last 72 hours.
In the last 72 hours, the cheapest one-way ticket from Ontario to Denver found on KAYAK was with Frontier for $37. Frontier proposed a round-trip connection from $53 and Delta from $196.

Which airlines fly most frequently between Ontario and Denver?

The airlines most regularly connecting Ontario to Denver are Southwest (4 flights per day), United Airlines (3 flights per day), and Frontier (2 flights per day).

Which airlines fly non-stop between Ontario and Denver?

Airline and price data is aggregated from results in KAYAK’s search results from the last 2 weeks for flights from Ontario to Denver.
There are 3 airlines that fly nonstop from Ontario to Denver. They are: Frontier, Southwest and United Airlines. The cheapest price of all airlines flying this route was found with Frontier at $51 for a one-way flight. On average, the best prices for this route can be found at Frontier.

How many flights are there between Ontario and Denver per day?

Each day, there are between 7 and 12 nonstop flights that take off from Ontario and land in Denver, with an average flight time of 2h 17m. The most common departure time is 5:00 am and most flights take off at night. Each week, there are 70 flights. The most frequent day of departure is Friday, when 17% of all weekly flights depart. The fewest flights depart on a Saturday.

Which cabin class options are there for flights between Ontario and Denver?

The average price of flights for each cabin class for the route found by users searching on KAYAK over the last 2 weeks.
There are 4 cabin class options for the route. These are First, Business, Economy and Prem Economy. Perform a search on KAYAK to find the latest prices and availability for all cabin fares, which differ across airlines.

How long does a flight from Ontario to Denver take?

A direct flight to Denver will take on average 2h 16m to travel the 817 miles flying distance from Ontario.

What’s the earliest departure time from Ontario to Denver?

Early birds can take the earliest flight from Ontario at 12:55 am and will be landing in Denver at 4:19 am.

What’s the latest departure time from Ontario to Denver?

If you prefer to fly at night, the latest flight from Ontario to Denver jets off at 8:56 pm and lands at 12:24 am.

Good to know

Low season

January

High season

July

Cheapest flight

$37
Best time to beat the crowds with an average 36% drop in price.
Most popular time to fly with an average 22% increase in price.
Flight from Ontario to Denver

When to book flights from Ontario to Denver

Are your dates flexible? Find out the best times to travel from Ontario to Denver based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Ontario to Denver

  • What are the transit options at Denver International Airport (DEN)?

    There is a large network of transit options that connect to Denver International Airport (DEN). You can use the airport rail serving the eight stations which runs regularly every 15min during the day and every 30min at night. Also, you can opt for ground transportation such as hotel shuttles, taxis, ride shares, and rental car shuttles. However, if you are in a hurry, the most convenient option is to use a taxi.

  • Can I exchange my foreign currency at Denver International Airport (DEN)?

    Denver International Airport (DEN) has three global money exchange locations. They are located in Gates A, B, and Jeppesen Terminal Level 5. You can also use the airport exchange kiosk, although they have the worst exchange rates.

  • What transportation option is available to Ontario Airport (ONT)?

    There are many ways you can get to Ontario Airport (ONT) from Ontario City Center. Public transits offer cheap and easy travel although takes longer to arrive at the airport. The station is right within ONT for easy passenger access. There is also the use of airport shuttles to provide transportation to passengers. Alternatively, you can use a taxi, which is the fastest way to get to the airport.

  • Are there nursing suites at Denver International Airport (DEN)?

    There are various options of nursing suites for passengers with kids at Denver International Airport (DEN). They are located at each of DEN’s concourses, offering excellent security and a peaceful environment to nurse after a long flight. Also, the suites are available throughout the day and night.

  • What is the cheapest flight from Ontario to Denver?

    In the last 3 days, the lowest price for a flight from Ontario to Denver was $37 for a one-way ticket and $53 for a round-trip.

  • Do I need a passport to fly between Ontario and Denver?

    No

  • Which airlines offer Wi-Fi service onboard planes from Ontario to Denver?

    All the following airlines offer inflight Wi-Fi service on the Ontario to Denver flight route: Delta, American Airlines, Alaska Airlines, JetBlue, Aeromexico, and British Airways.

  • Which aircraft models fly most regularly from Ontario to Denver?

    The Airbus A320neo is the aircraft model that flies most regularly on the Ontario to Denver flight route.

  • Which airline alliances offer flights from Ontario to Denver?

    Star Alliance is the only airline alliance operating flights between Ontario and Denver.

  • On which days can I fly direct from Ontario to Denver?

    There are nonstop flights from Ontario to Denver on a daily basis.

  • Which is the best airline for flights from Ontario to Denver, Delta or United Airlines?

    The two airlines most popular with KAYAK users for flights from Ontario to Denver are Delta and United Airlines. With an average price for the route of $256 and an overall rating of 8.0, Delta is the most popular choice. United Airlines is also a great choice for the route, with an average price of $303 and an overall rating of 7.4.

  • How does KAYAK find such low prices on flights from Ontario to Denver?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Ontario to Denver.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Ontario to Denver?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Denver from Ontario is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Ontario to Denver?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Denver with an airline and back to Ontario with another airline. Booking your flights between Ontario and DEN can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Ontario to Denver?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Denver from Ontario up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

See more FAQs

Top tips for finding a cheap flight from ONT to Denver

  • Looking for a cheap flight? 25% of our users found flights on this route for $95 or less one-way and $138 or less round-trip.
  • If you are flying out of Ontario Airport (ONT) and need to park, you will find various parking spots. There are long and short-term parking options depending on how long you want to park. The parking stalls are open throughout to every passenger who wishes to park offering the ultimate convenience. They are located in each terminal providing valet, premium, and general parking options.
  • When flying from Ontario Airport (ONT), it is recommended that you arrive at least 2h earlier before your scheduled flight. It is vital to consider the time you will take when checking in at the airport, getting boarding passes, and passing through security checks. Luckily, the Ontario Airport (ONT) waiting time is improving to excellent staffing and screening options.
  • There are multiple power stations in all terminals when you get to Denver International Airport (DEN) and need to work. The stations are well-equipped making it comfortable to work at your convenience.
  • With multiple lounges at Denver International Airport (DEN), passengers can take advantage of the services and refuel when waiting for the next flight or shuttle bus. All the lounges are easily accessible as they are located near passenger departures.
  • If you are having an early morning flight and looking for accommodation, there are various hotels near Ontario Airport (ONT) offering excellent services like free shuttle transfer to the airport. These hotels include Double Tree by Hilton Hotel located 0.9 miles from the airport and Holiday Inn Ontario Airport, which is around 0.7 miles from the airport.
See more tips

Prefer to fly non-stop from Ontario to Denver?

Find which airlines fly direct from Ontario to Denver Intl, which days they fly and book direct flights.

Nonstop departures

Ontario to Denver Intl

Monday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Tuesday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Wednesday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Thursday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Friday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Saturday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Sunday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

See more direct flights

Nonstop returns

Denver Intl to Ontario

Monday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Tuesday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Wednesday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Thursday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Friday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Saturday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

Sunday

Air Canada, Frontier, Southwest, +1 more

Air Canada, Frontier, +2 more

See more direct flights
See more direct flights

Top 4 airlines serving from Ontario to Denver

 
See real verified KAYAK customer reviews for airlines flying from Ontario to Denver. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Ontario to Denver? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
DeltaOverall score based on 10975 reviews
7.9comfort
8.6crew
8.0entertainment
8.2boarding
7.4food
Airline reviews

I'm a larger, athletic guy (6'2", 260lbs powerlifter) and I found the seats incredibly uncomfortable with minimal leg room, especially in a window seat. Now, I full understand that being smaller may change my view but even if I was 80lbs less, my legs would be the same size and I was sandwiched between my seat and the seat in front of me.

6.0 GoodDan, Apr 2024LGA - DEN
Read more about Delta reviews

I'm a larger, athletic guy (6'2", 260lbs powerlifter) and I found the seats incredibly uncomfortable with minimal leg room, especially in a window seat. Now, I full understand that being smaller may change my view but even if I was 80lbs less, my legs would be the same size and I was sandwiched between my seat and the seat in front of me.

There was a loud squeaky sound the whole time we were flying.

I didn’t not like that I could not select my seat and ended up with the worse seat.

The landing was bad and the hostess came two times and i was sleeping but when she served the person that nexts to me I woke up and she didn’t even asked me if I need any drink or snacks two times!!!!

The helpful attitude of the staff, and being a wheelchair passenger everyone was helpful and understanding. The trip was made comfortable by the upgraded seat which was given without my request, that was a great surprise. Thank you Delta.

Plane was late because of a mechanical malfunction and the food listed as available was not. Flight attendants seem over worked and under paid. They just done seem happy. And that can be seen in their faces.

Waited 3 hours on a plane to de-ice due to manpower issues. Waited another hour and a half once we landed because of a gate issue. Missed my connections. Created. A total of 13 hours of delay.

Great, on time departure, friendly and accommodating crew, great leg room, Smith flight

Plane was turned around due to fog half way into the flight, Delta did not properly direct passengers to stay on same flight and instead failed to properly rebook on Alaska

Like most domestic flights in the US, you are basically on your own with this airline when it comes to food, so be sure to purchase meals and drinks ahead of time or expect to arrive starving and dehydrated (like I was).

Positive: Entertainment via phone on the short was great and my first time. Good food and wine and head phones for free. Negative: Seat hardly reclined on the long flight. Breakfast was an egg with a bun. No egg choices and rather have something sweet like bun/jam and Youghurt.

They did get us booked on a later flight, but it made us miss our connecting flight. So, we had to stay and another state overnight with no luggage or clothes. Because they kept our luggage at airport for next flight on the next day.

Flight was on time. Staff were friendly. I paid for Economy Plus but was required to check my standard carry-on luggage due to lack of space on the aircraft. This cost me 30 minutes, unexpectedly, in waiting at the baggage claim. This experience did not meet my expectations.

Crew is way too many times on the intercom re explaining the same thing

Amazing comfortable chairs great snacks super friendly staff pilots did excellent job. Smooth sailing all the way. Definitely be flying United more.

We waited too long to get water while the plane was on the Tarmac awaiting de-icing.

The plane was delayed coming in and on the tarmac. I was coming from another flight so it made for a very long day. The stewardess kept trying to slam the overhead bins closed and I was worried that she had damaged my new luggage. They ran out of snacks and lccdsddd me a hummus box which was nice. It took them a very long time to pick up the garbage so I could not go to the washroom and had little time. To prepare for disbarment. The TV system was hard to control from the armrest and picture wasn’t clear. The crew did apologize several times for the lateness. It took the Denver airport an unusually long time to de-ice the plane.

By in large it was a good experience. The flight crew was great and that's the most important to me. Boarding was fine.

It was fine. Everything ran on time, crew was great.

Staff friendly and app worked really well. Modest delays were frustrating

The experience was great and much better than the flight going out. of course I was in first class but the service was excellent

Comfort of seats, ease of boarding. Food selection could be better

Food options were limited which is absolutely embarrassing for a Flight of this size The staff did not come around as much and I am not accustomed to such poor service from American Airlines Drinks I believe were limited to soda and water

Because I can’t stand very long in one place, I was allowed to reword.

Crew were attentive and friendly. Flight was smooth and early! I enjoyed the less crowded plane. Thank you!

We are gluten free, there were not any available complimentary gluten free options.

No meal on a cross country flight? SFO-MiA is pretty much the definition of a coast to coast flight. No meal provided. Sky high wi-fi rates too. Stop nickel and diming your customers.

The staff was unprofessional and didn’t communicate very well. The boarding process was very disheveled, potentially due to a power outage the previous day but there was no contingency plan to properly get passengers boarded the following day. Once boarded the aircraft stayed on the tarmac for over 45 minutes due to high winds. The communication was sporadic but an announcement was finally made an additional 30 minutes later that the flight was cancelled but we couldn’t get off the plane. Prior to deplaning one of the gate agents came on the plane and made an announcement for everyone to pickup their checked bags and take a card to rebook a new reservation because they didn’t have adequate staff. Flights were missed, passengers went to different airports and there was little to no assistance from AA.

Apart from the delay due to unforeseen circumstances. The leg from sjc to dfw was fine. It was the leg from dfw to orf that we encountered issues mainly due to the flight attendant crew not being friendly. We had two small children and we needed some assistance to warm up milk so the baby would sleep. The crew just didn’t get it and made things very difficult. One made a remark that the baby’s dirty diaper smell was a “gift” to the plane in a rude way. Normally I’d brush that off as a funny comment if the rest of the trip the attendants were helpful or understanding of the difficulty we faced. But that wasn’t the case. We were met with rudeness on the second leg. Whereas on the first leg the crew were so nice and helpful.

Flight From PHX to CVG was on time, very professional staff

There were 3 leg for the trip and each leg was delayed by 90 minutes or more. The boarding process takes forever with people waiting on the jetway even though most folks do not have carry-on. The whole process is poorly managed.

Not have to pay for every single item to take a flight. Seating and delays sucked.

Terrible. Seats are bad and the baggage policy is inconsistent

Everything was good, and most importantly on time. They have been extremely tardy in some of my flights

They lost my baggage on my connection flight, it’s been 24 hours since I put my claim in and still no update on my bags.

It’s a cheap airline. I wish they had better seats.

The only issues had were outside of Frontier’s control or weren’t expected. It was a two hour flight they completed fast. We landed almost an hour ahead of schedule. The issues with no entertainment or food weren’t issues since there was no expectations. The issue of the loud or crying babies was outside of frontiers control.

Seats are cramped and very uncomfortable. You have to pay for everything and it is too expensive.

Smooth process and flight. My favorite kind. Uneventful and on-time!

Xmas Day- Flights were on time for departure and arrival, baggage check in and boarding process were hassle free, baggage also arrived without any delay. Satisfied customer on this journey.

Book cheap flights from Ontario to Denver

Recent one-way flight deals

 
Only flying one-way? Below are some of the best one-way flight deals from Ontario to Denver found on KAYAK in the last 72 hours.
5/17Fri
nonstopFrontier
2h 21mONT-DEN
$37
5/6Mon
nonstopFrontier
2h 24mONT-DEN
$39
5/14Tue
nonstopFrontier
2h 24mONT-DEN
$40
5/25Sat
1 stopDelta
4h 56mONT-DEN
$108
5/31Fri
nonstopUnited Airlines
2h 26mONT-DEN
$120
5/24Fri
1 stopDelta
4h 54mONT-DEN
$139
6/9Sun
nonstopUnited Airlines
2h 17mONT-DEN
$140
5/30Thu
2 stopsAlaska Airlines
9h 37mONT-DEN
$177
5/15Wed
2 stopsAlaska Airlines
12h 29mONT-DEN
$182
5/8Wed
2 stopsAmerican Airlines
9h 35mONT-DEN
$447

Search by stops

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Last minute flights from Ontario to Denver

Last minute flight, train and bus deals

 
These last-minute flight deals are the cheapest flights found on KAYAK in the last 72 hours for flights from Ontario to Denver that are departing in the next 10 days.
4/30Tue
multi-stopFrontier
4h 34mONT-DEN
5/1Wed
nonstopFrontier
2h 24mDEN-ONT
$91
4/29Mon
nonstopFrontier
2h 24mONT-DEN
5/18Sat
nonstopFrontier
2h 24mDEN-ONT
$118
4/30Tue
multi-stopUnited Airlines
25h 52mONT-DEN
5/5Sun
multi-stopUnited Airlines
5h 01mDEN-ONT
$511
4/29Mon
multi-stopUnited Airlines
25h 52mONT-DEN
5/9Thu
multi-stopUnited Airlines
5h 01mDEN-ONT
$512
4/27Sat
multi-stop
10h 01mONT-DEN
4/29Mon
multi-stop
5h 35mDEN-ONT
$540
4/27Sat
multi-stop
10h 01mONT-DEN
4/28Sun
multi-stop
9h 04mDEN-ONT
$556
4/26Fri
multi-stopAmerican Airlines
4h 01mONT-DEN
4/26Fri
multi-stopAmerican Airlines
4h 06mDEN-ONT
$800
4/30Tue
multi-stopAmerican Airlines
9h 54mONT-DEN
5/14Tue
multi-stopAmerican Airlines
4h 42mDEN-ONT
$806
4/27Sat
multi-stopDelta
5h 14mONT-DEN
4/27Sat
multi-stopDelta
4h 22mDEN-ONT
$962
4/28Sun
multi-stopDelta
4h 52mONT-DEN
4/29Mon
multi-stopDelta
4h 44mDEN-ONT
$1,108

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Ontario - Denver Flights

Departure:

Ontario (ONT)United States

Destination:

Denver (DEN)United States

Return flight deals:

Denver - Ontario

Cabin classes:

$438
$977
$469
$64