$62 Cheap Flights from Denver (DEN) to Ontario (ONT)

Popular airlines from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)

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Cheap Flights from Denver to Ontario (DEN-ONT)

Prices were available within the past 7 days and start at $62 for one-way flights and $104 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Frontier Airlines
Frontier Airlines
Frontier Airlines
Frontier Airlines
Frontier Airlines
United
Southwest Airlines
Hawaiian Airlines
American Airlines

Find the cheapest month to fly from Denver (DEN) to Ontario (ONT)

April is typically the cheapest month to fly

From $48 - $88 per traveler.

Graph displaying average flight prices per month

Alternative airports near Ontario

Prices were available within the past 7 days. Prices and availability are subject to change.

Flights from Denver (DEN) to Ontario (ONT)
Origin airport
Denver Intl.
Destination airport
Los Angeles - Ontario Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, United
Roundtrip price
$104
Distance
816 mi
Average flight time
1 hour 19 mins

Denver to Ontario Flights

The cheapest times to fly from Denver to Ontario

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Denver to Ontario are during the month of September. You can find some of the cheapest flights from Denver to Ontario with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Denver to Ontario

Sunday is one of the best days to book for cheap flights from Denver to Ontario: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Denver to Ontario

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Denver to Ontario in 2025. You can also book with separate airlines for your outbound and return journeys, from $62 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Denver to Ontario flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Denver to Ontario airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) cost?
Cheap return fares from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) start at $114. This information is based on the cheapest price found on Expedia for this return journey departing within the next three months. This airfare is for a Frontier Airlines flight leaving DEN on August 13 2025 and touching down at ONT. The price was last updated on July 19 2025 and has not changed since.
What is the cheapest month to fly from DEN to ONT?
The cheapest flights from DEN to ONT are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
Which airlines fly direct from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
Take your pick of 3 airlines that operate direct flights from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT). Including:

  • Southwest Airlines
  • United Airlines
  • Frontier Airlines

What is the cheapest airline that flies from DEN to ONT?
Currently, the cheapest airline operating one-way flights from DEN to ONT is Frontier Airlines. You can book a seat on this route from $64. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from DEN on October 8 2025. Prices were last updated on July 19 2025 and have not changed since.
How many flights per day from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
With an average of 6 direct flights departing from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) every day, you'll be cruising above the clouds before you know it.
What are the most popular departure times for flights from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
More people fly between DEN and ONT at 11 AM than at any other time of day. Looking to skip the crowds? Try choosing a quieter departure window and there's a chance you'll save on your ticket as well.
What day of the week has the most flights from DEN to ONT?
If you travel on a Friday, you'll get the biggest range of choices for flights from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT).
What is the earliest flight from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
Denver Intl. Airport (DEN)'s earliest flight to Los Angeles - Ontario Intl. Airport (ONT) is at approximately 8:07AM UTC-7. With a travel duration of 2h 33m, you'll arrive at around 9:40AM UTC-8.
How long does it take to fly from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
The average flight time from DEN to ONT is 2 hours and 27 minutes, covering a distance of 820 mi.
What is the best time to fly from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
Opt for a flight from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) that leaves before 3 PM to reduce the likelihood of delays. Later departures are on average 22% more likely to be canceled.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports do you fly into for Ontario from Denver Intl. Airport (DEN)?
Land at any of these Ontario hubs after your direct flight from Denver Intl. Airport (DEN):

  • Los Angeles Intl. Airport (LAX)
  • John Wayne Airport (SNA)
  • Bob Hope Airport (BUR)
  • Los Angeles - Ontario Intl. Airport (ONT)
  • Long Beach Municipal Airport (LGB)

Is it cheaper to buy a plane ticket from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) last-minute?
Booking your flight from DEN to ONT shortly before your getaway is usually more expensive. However, if there's some wiggle room with your travel dates and times, you could score a cheap last-minute fare.
Is it cheaper to book a DEN to ONT flight and hotel package?
Opting for a DEN to ONT flight and hotel package is typically cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your trip in one place. Pick from our extensive range of hotels and then add activities, flights and car rentals to your booking. Bundle everything together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
Generally, it's possible to reschedule or cancel your DEN to ONT flight. However, for bookings made more than 24 hours ago, additional fees may apply. Check your airline's policies in your itinerary to see what changes are possible and whether any costs are involved. You'll also find more details on our Customer Service portal.

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