DEN - ONT

$59 Find Cheap Flights from Denver to Ontario

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Denver to Ontario departing on 8/4. 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
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Ontario

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Denver to Ontario, 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 Denver to Ontario, as well as popular online travel agencies
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Flights Deals

Cheap Flights from Denver to Ontario (DEN-ONT)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Denver to Ontario 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 for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Denver to Ontario

Tue, Aug 5 - Mon, Aug 11
Frontier Logo
7:49 am - 9:09 amDEN-ONT
2h 20mnonstop
Frontier Logo
12:59 am - 4:19 amONT-DEN
2h 20mnonstop
$116Frontier
Find Deal
Mon, Aug 4 - Thu, Aug 7
Frontier Logo
10:29 pm - 11:50 pmDEN-ONT
2h 21mnonstop
Frontier Logo
5:21 pm - 8:44 pmONT-DEN
2h 23mnonstop
$118Frontier
Find Deal
Thu, Aug 21 - Mon, Aug 25
Southwest Logo
8:30 am - 9:45 amDEN-ONT
2h 15mnonstop
Southwest Logo
3:30 pm - 6:45 pmONT-DEN
2h 15mnonstop
$157Southwest
Find Deal
Thu, Aug 21 - Mon, Aug 25
Southwest Logo
5:20 pm - 9:05 pmDEN-ONT
4h 45m1 stop
Southwest Logo
1:25 pm - 4:35 pmONT-DEN
2h 10mnonstop
$167Southwest
Find Deal
Thu, Sep 25 - Sat, Sep 27
American Airlines Logo
12:14 pm - 4:05 pmDEN-ONT
4h 51m1 stop
American Airlines Logo
1:10 pm - 6:07 pmONT-DEN
3h 57m1 stop
$182American Airlines
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Sat, Sep 20 - Sat, Sep 27
American Airlines Logo
3:07 pm - 6:11 pmDEN-ONT
4h 04m1 stop
American Airlines Logo
1:10 pm - 6:07 pmONT-DEN
3h 57m1 stop
$187American Airlines
Find Deal
Thu, Sep 11 - Mon, Sep 15
Alaska Airlines Logo
6:17 pm - 11:53 pmDEN-ONT
6h 36m1 stop
Alaska Airlines Logo
11:39 am - 9:47 pmONT-DEN
9h 08m1 stop
$206Alaska Airlines
Find Deal
Fri, Sep 19 - Mon, Sep 22
Delta Logo
6:25 pm - 11:46 pmDEN-ONT
6h 21m1 stop
Delta Logo
5:05 pm - 10:33 pmONT-DEN
4h 28m1 stop
$222Delta
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Sat, Sep 20 - Sun, Sep 28
Delta Logo
5:30 am - 9:06 amDEN-ONT
4h 36m1 stop
Delta Logo
5:05 pm - 10:33 pmONT-DEN
4h 28m1 stop
$227Delta
Find Deal
Fri, Sep 5 - Mon, Sep 8
Alaska Airlines Logo
6:17 pm - 11:53 pmDEN-ONT
6h 36m1 stop
Alaska Airlines Logo
11:39 am - 9:47 pmONT-DEN
9h 08m1 stop
$268Alaska Airlines
Find Deal
Expert advice

Expert advice for your flight from Denver to Ontario

 
Snippets provided in this section are AI-generated based on a summarization of KAYAK-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Airlines
Frontier

Frontier's Economy Bundle includes a carry-on bag and Standard seat choice, ideal for budget travelers.


Frontier's Premium Bundle offers extra legroom and priority boarding for a small additional cost.

Read more about Frontierby Stefanie Waldek
United Airlines

United's Economy Plus offers up to six inches more legroom than standard economy seats.


United's Priority Boarding can secure overhead bin space by placing you in Zone 2.

Airports
DEN

Use the DEN Reserve program for expedited security. Reserve slots online up to 3 days in advance for a smoother departure experience.

Read more about DENby Harriet Baskas
ONT

Take the ONT Connect Shuttle from Rancho Cucamonga Station for a seamless transfer to the airport. It's included in the Metrolink fare.

Read more about ONTby Jennifer Simonson
Our travel experts
Stefanie Waldek

Stefanie Waldek

Expert on Frontier and United Airlines

Stefanie Waldek

Stefanie Waldek

Stefanie Waldek is a freelance space, travel, and design writer based in Saratoga Springs, NY. Her words have appeared in Space.com, Travel + Leisure, Condé Nast Traveler, Architectural Digest, and House Beautiful, among other publications. An expert in aviation and expedition cruising, Stefanie is frequently up in the air or on the sea, likely en route to Antarctica or the Arctic.

Read more
Jennifer Simonson

Jennifer Simonson

Expert on ONT

Jennifer Simonson

Jennifer Simonson

Jennifer Simonson is driven by her lifelong commitment to exploring the globe. Her insatiable curiosity had led her to immerse herself into diverse locations like Oklahoma City and Pismo. Her hotel recommendations are the result of the myriad hotels she's stayed at across her travels. Along her journey, she cherishes engaging conversations with locals, indulging in the finest ice cream, trying her hand at surfing, and embarking on nature-filled hikes.

Read more
Harriet Baskas

Harriet Baskas

Expert on DEN

Harriet Baskas

Harriet Baskas

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Read more
Useful Info

KAYAK's insights & trends for Denver to Ontario flights

Get data-powered insights and trends into flights from Denver to Ontario 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 Denver to Ontario?

The average price of all round-trip flights from Denver to Ontario clicked on KAYAK for each day over the last 12 months.

When flying from Denver to Ontario, you should consider leaving on a Saturday and avoid Sundays if you are looking for the best rates. For your return to Denver, you’ll find the best rates on Saturdays and the most expensive ones on Sundays.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Denver to Ontario, 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 Denver to Ontario is January, where tickets cost $115 (return) on average. On the other hand, the most expensive months are June and February, where the average cost of round-trip tickets is $191 and $186 respectively.

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

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Denver to Ontario, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Denver to Ontario, you should book around 2 weeks before departure. For the absolute cheapest price, our data suggests you should book 4 weeks before departure.

Good to know

Low seasonApril
High seasonNovember
Cheapest flight$59
Best time to beat the crowds but there is an average 9% increase in price.
Most popular time to fly with an average 9% increase in price.
Flight from Denver to Ontario

When to book flights from Denver to Ontario

Are your dates flexible? Find out the best times to travel from Denver to Ontario 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 Denver to Ontario

  • Where can I find a taxi to travel aboard at ONT?

    Suppose you want to travel from ONT to your destination of choice in Ontario with a taxi. In that case, you can easily find one to travel aboard on the curbside outside the International Arrivals Terminal. As taxis from the airport to ONT travel faster than the public buses that serve this route, traveling aboard a taxi would be wise if you want to travel quickly.

  • Does ONT have on-site restaurants?

    ONT has plenty of restaurants. In this airport's Terminal 2, you can eat at Cross Grain Brewhouse, Harvest & Grounds, and Wolfgang Puck Pizza, while in Terminal 4, you can grab a bite at Coffee Bean & Tea Leaf, Rock & Brews, and Wahoo's Fish Tacos.

  • Where is long-term parking at DEN?

    If you'd like to park your car long-term at DEN, you can do so at three long-term on-site parking options at DEN. They include the East and West Economy Lots, Pikes Peak Lot, and Mt. Elbert Lot. You can count on finding your car intact upon return at any of these lots, as they all boast tight security.

  • Does DEN have a prayer room?

    If you want to pray privately before departing DEN, you'll get the chance to do so, given that DEN is home to a prayer room on the East Side of the Jeppesen Terminal. You'll be allowed to enter this room, irrespective of religion, as it is an interfaith chapel. Since this room is open 24h a day, you can visit it anytime.

  • What is the cheapest flight from Denver to Ontario?

    In the last 3 days, the lowest price for a flight from Denver to Ontario was $59 for a one-way ticket and $116 for a round-trip.

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

    A passport is not required to fly from Denver to Ontario.

  • Which airports will I be using when flying from Denver to Ontario?

    Denver and Ontario are both served by 1 main airport. You will leave Denver from Denver Intl and will be arriving at Ontario.

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

    Delta, Alaska Airlines, American Airlines, and Hawaiian Airlines offer inflight Wi-Fi service on the Denver to Ontario flight route.

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

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

  • Which airline alliances offer flights from Denver to Ontario?

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

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

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

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

    The two airlines most popular with KAYAK users for flights from Denver to Ontario are Southwest and United Airlines. With an average price for the route of $252 and an overall rating of 8.0, Southwest is the most popular choice. United Airlines is also a great choice for the route, with an average price of $284 and an overall rating of 7.4.

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

    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 Denver to Ontario.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Ontario from Denver 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 Denver to Ontario?

    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 Ontario with an airline and back to Denver with another airline. Booking your flights between Denver and ONT 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 Denver to Ontario?

    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 Ontario from Denver up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Denver to Ontario

  • Looking for a cheap flight? 25% of our users found flights on this route for $106 or less one-way and $137 or less round-trip.
  • To have adequate time to go through Denver International Airport's (DEN) security checkpoints, you should reach the airport at least 2h ahead of your flight. Apart from going through the airport's checkpoints in time for your flight, if you reach the airport as early as advised, you'll get the chance to visit the airport's points of interest.
  • While waiting for your flight to Ontario International Airport (ONT) at DEN, you can relax at American Airlines Admirals Club, United Club, or Delta Sky Club. To enter any of these lounges, you must pay an entrance fee and show that you are traveling with the airline it is affiliated with. Delta Sky Club and American Airlines Admirals Club are found in Concourse A, while United Club has two locations in Concourse B.
  • In case you're traveling with a lactating baby, you can privately breastfeed him/her at DEN. This is because DEN features nursing rooms equipped with comfortable seating, sinks, power outlets, and privacy curtains near the center of Gates A, B, and C.
  • At ONT, you can easily withdraw the money you need before stepping out of the airport, as it features operational ATMs. These ATMs are on the upper and lower levels of Terminals 2 and 4, near the front entrance of the International Terminal, and in the airport's Rental Car Facility.
  • You should head to one of ONT's information desks if you have any inquiries. It's worth noting that you can count on getting fully answered at any of these desks in Terminals 2 and 4, as they feature well-informed airport staff.

Prefer to fly direct from Denver to Ontario?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Denver Intl to Ontario.
Find which airlines fly direct from Denver Intl Airport to Ontario Airport, which days they fly and book direct flights.

Direct departures

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

Direct returns

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

Reviews of the top 3 airlines serving from Denver to Ontario

 
See real verified KAYAK customer reviews for airlines flying from Denver to Ontario. 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 Denver to Ontario? 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
SouthwestOverall score based on 4278 reviews
7.6Entertainment
8.2Boarding
8.6Crew
7.1Food
8.0Comfort
Airline reviews

I would have liked to arrive on time - not 5 hours late!

4.0 OkayAnonymous, Apr 2025DEN - SEA
Read more Southwest reviews

I would have liked to arrive on time - not 5 hours late!

It was a perfect flight in all aspects! Both legs!

Boarding process, crew were good. But the seats were so uncomfortable that was all I could focus on. I literally had to sit forward so that all 3 of us could fit in row. I will try to avoid Southwest in the future for any flights over 60 minutes.

1.5 hour delay, poor service, no compassion from the crew. Terrible experience

Great flight, 47 passengers on a 180 seat plane. Stewardess was pleasant and cheerful.

Great experience flying Southwest. The crew was really kind and helpful, and very friendly with our toddler.

Our flight was diverted from being a non-stop to getting within 150 miles and requiring another plane. We heard 4 or 5 different versions from SW as to why we had to stop, then wait for a replacement plane. Five hour delay, weather did not come up as a single excuse.... communication was not clear and well explained. No one really took charge!

Plane late from DC to Austin 30 minutes. Crew made up much of the time enroute to San Diego.

I really like open seating. I hate that I've heard this is going away. This is one of the unique things that makes Southwest my goto choice.

Fine, but how to board on SW versus othrr airlines, is just lame. Goood staff though and all was solid otherwise.

Impressed with the service despite turbulence because of the weather. Both flights arrived before their scheduled times.

Great experience…left a bit behind schedule but made up fir that in the air and landed 10 minutes early 😁

Electric plugs didn't work. Entertainment system wasn't working

The design of the light switch on the arm rest is ridiculous.

The gate attendant let me walk right by her with a bag too big for the overhead compartment

Overall, it was a good experience. Boarding was good and there was plenty of overhead bin space for everyone’s carryons (even when we boarded toward the end). Only improvement would be to offer trash service more regularly.

David went above and beyond to make our flight the best that it could be

No food service almost missed because of first flight delays

Had a hard time finding my assigned seat. No attendants to assist.

The negative was the wait at the airport coming back. I checked my bags in, an hour before boarding and I get the notification that my flight was delayed. Rather had gotten the notification while I was at the hotel. Then it was delayed 3 x’s. Ugh!

The worst. We never made our connection and they did absolutely nothing to help us at the airport.

I never got to experience the flight because they delayed my first flight and I missed this one. Then Frontier didn't want to help me rebook a flight to get me to my final destination.

The Boarding process in Denver was chaotic, and since the line was so long, we were lined up very far from the gate. If there were any announcements from the gate staff, we didn't hear them. The flight attendants were spectacular. The only negative part of the flight was sitting by a 2 1/2 year old who was unruly and unfortunately had parents that matched his behaviors. Also, the restaurants in Denver on the E concourse, they didn't have food (passengers could only order 1 item on the entire menu) or the restaurants had 12-14 people waiting for orders to be prepared and another 6 people waiting to order. If you have a layover in Denver and need to grab food, be prepared to visit the shops with pre-packaged sandwiches, or you can visit another concourse but it may take a while to transit throughout the airport.

Everything went as planned. Crew was great. Seats were still not that comfortable.

they delayed my flight which ended up, causing my layover flight to leave without me, resulting in me missing a flight and having to stay overnight in Houston international. I got no compensation other than a flight to my original location only a day later. i’ve never experienced such a unprofessional situation

The seats were extremely hard and uncomfortable, even for a budget airline.

Boarding was very well executed. Got my bag right away.

Overall experience good. There was no food and seats were not terribly comfortable.

There was nothing to like, flight delayed had to move to different departure areas, disorganized to say the leasr

There were a lot of issues every step of the process. Check in, security, boarding, and dealing with luggage. Plus the money you think you are saving you end up using in hidden fees.

Everything you need to know for your flight from Denver to Ontario

Information on your arrival and departure airports

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