$49 Cheap Frontier Airlines flights Denver (DEN) to Ontario (ONT)

View $49 flight on Wed, Sep 17, 2025Opens in a new window

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$49 Cheap Frontier Airlines flights Denver (DEN) to Ontario (ONT)

Prices were available within the past 7 days and start at $49 for one-way flights and $90 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Tue, Sep 16 - Sat, Sep 20
DEN
Denver
ONT
Ontario
$90 Roundtrip, just found
$90
Roundtrip
just found
Select Frontier Airlines flight, departing Tue, Sep 16 from Denver to Ontario, returning Sat, Sep 20, priced at $90 just found
Frontier Airlines
Wed, Sep 10 - Tue, Sep 16
DEN
Denver
ONT
Ontario
$91 Roundtrip, found 1 hour ago
$91
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Wed, Sep 10 from Denver to Ontario, returning Tue, Sep 16, priced at $91 found 1 hour ago
Frontier Airlines
Sat, Sep 20 - Wed, Oct 8
DEN
Denver
ONT
Ontario
$98 Roundtrip, found 9 hours ago
$98
Roundtrip
found 9 hours ago
Select Frontier Airlines flight, departing Sat, Sep 20 from Denver to Ontario, returning Wed, Oct 8, priced at $98 found 9 hours ago
Frontier Airlines
Sat, Sep 13 - Wed, Sep 17
DEN
Denver
ONT
Ontario
$99 Roundtrip, found 6 hours ago
$99
Roundtrip
found 6 hours ago
Select Frontier Airlines flight, departing Sat, Sep 13 from Denver to Ontario, returning Wed, Sep 17, priced at $99 found 6 hours ago
Frontier Airlines
Tue, Sep 23 - Mon, Sep 29
DEN
Denver
ONT
Ontario
$100 Roundtrip, found 1 hour ago
$100
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Tue, Sep 23 from Denver to Ontario, returning Mon, Sep 29, priced at $100 found 1 hour ago
Frontier Airlines
Wed, Sep 3 - Thu, Sep 4
DEN
Denver
ONT
Ontario
$104 Roundtrip, found 6 hours ago
$104
Roundtrip
found 6 hours ago
Select Frontier Airlines flight, departing Wed, Sep 3 from Denver to Ontario, returning Thu, Sep 4, priced at $104 found 6 hours ago
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
Popular airline
Frontier Airlines
Distance
816 mi
Average flight time
1 hour 18 mins

Frequently asked questions

How much is a Frontier Airlines flight from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
Grab cheap return Frontier Airlines flights from $90 from DEN to ONT by sorting your results from "Price (lowest to highest)" on Expedia. Or search for deals from $49 for a one-way trip.**These prices were available on Expedia within the past 7 days, for flights departing within the next year. Prices and availability are subject to change. Additional terms apply.
What is the cheapest month to fly from DEN to ONT with Frontier Airlines?
Frontier Airlines flights to Ontario are usually more affordable in the quieter months of January and April. Whether you're searching for a one-way or a return ticket, you could find a better deal then.
What is the cheapest time to book flights from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) with Frontier Airlines?
Start searching one to three months ahead of your travel date to get cheap fares on Frontier Airlines flights from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT). You can save 25% by booking your domestic flight 34 to 86 days in advance compared to last-minute reservations made 6 to 12 days out. You could also reduce costs by buying your fare on a Sunday, as it's 6% cheaper on average than a Monday, the most expensive day to book.* Nail your timing, and you can enjoy significant savings on domestic journeys.*Ideal booking window recommendation is based on average round-trip ticket prices for January through November for 2024. Best day of the week to book recommendation is based on average round-trip ticket prices for January through October 2024. All data sourced from ARC's global airline sales database.
Does Frontier Airlines fly nonstop from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
Skip the layovers and fly from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) on any of Frontier Airlines's 10 weekly direct flights. Use Expedia's "Nonstop" and "Airline" filters to find the Frontier Airlines flight that'll arrive at ONT at your preferred time.
How long does it take to fly from DEN to ONT with Frontier Airlines?
It takes around 2h 31m to travel nonstop from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) with Frontier Airlines.
Which day of the week has the most Frontier Airlines flights from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
If it's flexibility you're after, Wednesday offers the most choice for Frontier Airlines flights from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT). You can select from 2 different departures.
What is the earliest Frontier Airlines flight from DEN to ONT?
Leaving DEN at 8:07AM UTC-7, the first Frontier Airlines flight to ONT lands at 9:40AM UTC-8. Traveling early means you're less likely to experience delays.* After something later? The last Frontier Airlines flight from DEN to ONT departs at 10:15PM UTC-7 and touches down at 11:47PM UTC-8.*Most reliable time of the day recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports does Frontier Airlines fly into in Ontario?
When heading from Denver Intl. Airport (DEN) to Ontario with Frontier Airlines, you're most likely to land at Los Angeles - Ontario Intl. Airport (ONT). This is the airline's main hub here. Other nearby airports like Los Angeles Intl. Airport (LAX) and John Wayne Airport (SNA) may have lower fares, so it's a good idea to consider all available options on Expedia.
Why fly with Frontier Airlines from DEN to ONT?
Journey from DEN to ONT with Frontier Airlines and enjoy a range of benefits starting with a rewarding loyalty program. When booking through Expedia as a Frontier Miles and One Key™ member, you may also earn OneKeyCash™* to redeem on select future travel purchases.*OneKeyCash™ disclaimer - OneKeyCash™ is not redeemable for cash and can only be used on Expedia, Hotels.com and Vrbo.
What type of plane does Frontier Airlines fly from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
For the Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT) route, Frontier Airlines typically operates Airbus A321neo and Airbus A320neo planes. Remember that last-minute changes can occur for operational purposes, so your flight could be on a different aircraft.
Can I change or cancel my Frontier Airlines flight from Denver Intl. Airport (DEN) to Los Angeles - Ontario Intl. Airport (ONT)?
Changes are often free within 24 hours of making a booking, but your airline may charge you after that. For more information about altering your reservation, go to your "Trips," select your flight and click on "Manage Booking." If you want the freedom to change your itinerary without being charged, tick the "No cancel fee" or "Changes included" filter when planning your next adventure.

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