Cheap flights from Denver to Ontario (DEN - ONT) from $21

This is the cheapest one-way flight price, found on 9/28. Prices may vary by date and flight preferences.
DEN — ONT
Oct 3 — Oct 101

The best prices from Denver Intl to Ontario are usually found in January or February, booked 53 days in advance, depart on a Wednesday or Thursday and return on a Wednesday

How to find the cheapest flight from Denver (DEN) to Ontario (ONT)

All the information you need to plan the best DEN to ONT flight in 2023: compare Denver to Ontario flight prices with the expected peak season, weather and rainfall in Ontario.

Popular in

June

Cheapest in

January

Round-trip from

$217

One-way from

$21
High demand for flights, 17% potential price rise
Best time to find cheap flights, 43% potential price drop
From Denver Intl to Ontario
One-way flight from Denver Intl to Ontario

DEN - LAX

Price

$217 - $494

LAX

Temperature

57.2 - 73.4 °F

LAX

Rainfall

0 - 3.4 inches

What is the cheapest day to fly round-trip from Denver to Ontario?

Tuesday is generally a great day to depart. Flying on this day could help you save up to 62%.

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

To save on the cost of your flight from Denver to Ontario, book at least 56 days before your planned departure. Booking around this time can save you about 64% on the cost of this flight compared to booking a flight leaving this week. We have found prices from $267 if you need a flight within two weeks. For flights within the next 72 hours, you can find tickets from as low as $349.

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

January is one of the best times of the year to fly to Ontario from Denver. Prices for January average $231 per person but you can even find prices for as low as $79. The most expensive prices can be found in the month of May. Opting for a January flight can save you 37% on your journey compared to booking in May

When is the cheapest time to fly from Denver to Ontario (DEN - ONT)?

One of the essential ways to save on airfare from Denver to Ontario is to remain as flexible as possible. Flights that are at noon tend to be the most expensive. A flight in the afternoon could potentially save you up to 55% on airfare.

Cheap Frontier flights from Denver to Ontario

Find some of the cheapest Frontier flights traveling from Denver to Ontario. Come back soon if you're not finding the exact deal you're looking for.
  • One of the most popular airlines traveling from Denver to Ontario is Frontier. Flights from Frontier traveling this route typically cost $300.90 RT. This price is typically 13% cheaper than other airlines that offer Denver to Ontario flights. When booking this route, the cheapest RT price found was $119. Denver Intl Airport is the most common Denver airport to take off from when flying to Ontario. Ontario Airport is the most popular arrival airport in Ontario. When flying from Denver to Ontario, Frontier flights are 7% more popular than any other airline flying that same route.

Cheap Alaska Airlines flights from Denver to Ontario

To aid your search, here are some of the cheapest Alaska Airlines flights we've found from Denver to Ontario. Deals are refreshing constantly so come back soon for more options.
  • Alaska Airlines is one of the most popular airlines used for those traveling from Denver to Ontario. Flights on this route from Alaska Airlines typically cost $142.97 RT, a price that is 287% cheaper than the average Denver to Ontario flight. The cheapest flight found was $56 RT. Denver Intl Airport is the most common Denver airport to take off from when flying to Ontario. Ontario Airport is the most popular arrival airport in Ontario. When flying from Denver to Ontario, Alaska Airlines flights are -16% more popular than any other airline flying that same route.

Cheap Denver to Ontario flights in September & October 2023

The best prices found for DEN to ONT flights for September, October
These are some of the best deals we've found on flights to Ontario in 2023 at this time. For more flight deals, be sure to check back very soon.

Denver to Ontario 2023 flight deals

Cheap flights to Ontario from Denver found for this year
These are some of the best deals we've found on flights to Ontario in 2023 at this time. For more flight deals, be sure to check back very soon.

Non-stop flights to Ontario from Denver

Save time with Denver to Ontario direct flight deals
If you're seeking options on non-stop flights from Denver to Ontario, check out these fares. Select from other flights from Denver to Ontario by using the search form above.

Denver to Ontario flights leaving soon

Late deals on return flights to Ontario from Denver, departing today and this week
Users seeking a last-minute flight from Denver to Ontario should consider booking one of these fares. It's wise to confirm all flight details are correct before booking.

One-way flights to Ontario from Denver

The cheapest one-way flights from Denver to Ontario
Users traveling one-way from Denver to Ontario can select one of these great deals. Users in need of a round-trip flight from Denver to Ontario instead should update the search form at the top of page.

Find flights from Denver to Ontario within your budget

Use the slider to find flights from Denver to Ontario that fit your budget.

Fly from

Any airport

Fly to

Any airport

Budget

$38 - $177

Route

Depart

Return

Price

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Sat 11/4

Nonstop2h 31m

Ontario

Wed 11/8

Nonstop2h 22m

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Wed 10/18

Nonstop2h 31m

Ontario

Wed 10/25

Nonstop2h 24m

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Wed 12/6

Nonstop2h 31m

Ontario

Sat 12/9

Nonstop2h 22m

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Wed 10/25

Nonstop2h 31m

Ontario

Wed 11/1

Nonstop2h 24m

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Wed 11/1

Nonstop2h 31m

Ontario

Wed 11/8

Nonstop2h 22m

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Wed 10/25

Nonstop2h 31m

Ontario

Wed 11/1

Nonstop2h 22m

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Tue 10/31

Nonstop2h 31m

Ontario

Mon 11/13

Nonstop2h 20m

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Thu 10/26

1 stop7h 43m

Ontario

Mon 10/30

2 stops7h 11m

Denver IntlOntario

DEN - ONT

DENONT

Denver Intl

Tue 10/31

1 stop4h 38m

Ontario

Wed 11/15

1 stop4h 08m

Flights are sorted by cheapest first

Deals found on 9/27

Reviews of airlines servicing Ontario

To help decide which airline to fly from Denver to Ontario, see what other customers have to say about Frontier, Alaska Airlines and American Airlines. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.1
Very good
1,394 reviews

Entertainment

7.2

Boarding

8.3

Comfort

8.0

Food

7.2

Overall

8.1

Crew

8.6

Reviews

1 / 10

Flight departed on time and landed a little early. Friendly staff, and they did two passes with drinks and complimentary snacks.

Alaska Airlines
8.1
Very good
1,394 reviews
Alaska Airlines
8.1
Very good
1,394 reviews

Entertainment

7.2

Boarding

8.3

Comfort

8.0

Food

7.2

Overall

8.1

Crew

8.6

Reviews

1 / 10

Flight departed on time and landed a little early. Friendly staff, and they did two passes with drinks and complimentary snacks.

Delta
7.9
Good
3,023 reviews
Alaska Airlines
8.1
Very good
1,394 reviews

Entertainment

7.2

Boarding

8.3

Comfort

8.0

Food

7.2

Overall

8.1

Crew

8.6

Reviews

1 / 10

Flight departed on time and landed a little early. Friendly staff, and they did two passes with drinks and complimentary snacks.

Southwest
7.6
Good
1,521 reviews
Alaska Airlines
8.1
Very good
1,394 reviews

Entertainment

7.2

Boarding

8.3

Comfort

8.0

Food

7.2

Overall

8.1

Crew

8.6

Reviews

1 / 10

Flight departed on time and landed a little early. Friendly staff, and they did two passes with drinks and complimentary snacks.

United Airlines
7.4
Good
1,890 reviews
Alaska Airlines
8.1
Very good
1,394 reviews

Entertainment

7.2

Boarding

8.3

Comfort

8.0

Food

7.2

Overall

8.1

Crew

8.6

Reviews

1 / 10

Flight departed on time and landed a little early. Friendly staff, and they did two passes with drinks and complimentary snacks.

American Airlines
7.2
Good
2,635 reviews
Alaska Airlines
8.1
Very good
1,394 reviews

Entertainment

7.2

Boarding

8.3

Comfort

8.0

Food

7.2

Overall

8.1

Crew

8.6

Reviews

1 / 10

Flight departed on time and landed a little early. Friendly staff, and they did two passes with drinks and complimentary snacks.

Related info for your journey

Useful info, stats and facts about Denver to Ontario flights.

What airports do I use to fly from Denver to Ontario?

You will need to book a flight from Denver Intl to Ontario if you want to fly from Denver to Ontario. At least 5 different airlines have flights from Denver Intl (DEN) to Ontario (ONT) on a regular basis. There are 9 flights to Ontario from the Denver airport per day. If you manage to book one that is nonstop, then you can expect the flight time from DEN to ONT to be around 2h 15m.

Can I find flights from Denver to Ontario for under $100 on Cheapflights?

Yes, there are multiple flights from Denver to Ontario for under $100. The cheapest flight booked recently is on Frontier for just $38, but on average you can expect to pay $55.

Are there nonstop flights from Denver to Ontario for under $100 on Cheapflights?

Cheapflights has at least 20 direct flights from Denver to Ontario under $100. A good price for a nonstop flight from Denver to Ontario is less than $57.

Are there last-minute flights available from Denver to Ontario for under $100?

There are currently 20+ open flights from Denver to Ontario within the next 7 days for less than $100.

What days are nonstop flights available from Denver to Ontario?

Days when nonstop flights are available for this flight are: Sunday, Monday, Tuesday, Thursday, Friday, Saturday.

How popular is this Denver to Ontario flight route?

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

On average 22 flights depart from Denver to Ontario per day.
Morning (6am - Noon) - 41% of flight departures
Afternoon (Noon - 6pm) - 14% of flight departures
Evening (6pm - Midnight) - 45% of flight departures

How long is the flight from Denver to Ontario?

There are many flights that can get you from Denver to Ontario in 2h 31m. Fly via Frontier to get the fastest option. Airlines will cover a distance of 822 mi. All flights are typically nonstop.

What is the cheapest airline to fly from Denver to Ontario round-trip?

According to our current data, Frontier ($38), offers the cheapest pricing from Denver to Ontario. Frontier is priced at 76% lower than the current average price of a flight leaving 3 months from now.

What are the most popular airlines that fly from Denver to Ontario?

What are the most reliable airlines from Denver to Ontario?

Before booking your flight to Ontario from Denver, check out the most reliable airlines to get you to your destination on time: United Airlines (82%), Air Canada (71%), Southwest( 63%).

What are the cheapest flights from Denver to Ontario?

The cheapest flight price from Denver to Ontario is $25. On average you can expect to pay $122. The most popular route, (Denver Intl - Ontario), can usually be booked for $38.

What does DEN to ONT mean?

Denver Intl Airport is DEN and Ontario Airport is ONT. These codes are created by the International Air Transport Association (IATA) and airlines use them to identify the departing and arrival airports in the flight routes they service.

Alternative routes for Denver to Ontario

See prices for flight routes from nearby airports that may be better suited for you.

Top 5 airlines flying from Denver to Ontario

The chart below displays the airlines Cheapflights users traveling from Denver to Ontario choose most often. Cheapest and average prices are based on aggregated data from the past 12 months.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$56Average$143FlexibilityNo cancel feeOn-time62%
Search Frontier flights
DeltaCheapest$92Average$310FlexibilityNo cancel feeOn-timeN/A
Search Delta flights
Spirit AirlinesCheapest$111Average$179FlexibilityNo cancel feeOn-time65%
Search Spirit Airlines flights
United AirlinesCheapest$119Average$301FlexibilityNo cancel feeOn-time69%
Search United Airlines flights
American AirlinesCheapest$215Average$444FlexibilityNo cancel feeOn-time71%
Search American Airlines flights

Hourly flight availability from Denver to Ontario

See what time of day planes typically take off from Denver to Ontario
7%of flight departuresEarly morningMidnight to 6 am
45%of flight departuresMorning6 am to noon
6%of flight departuresAfternoonNoon to 6 pm
42%of flight departuresEvening6 pm to midnight
Midnight
6 AM
Noon
6 PM

Weekly flight availability from Denver to Ontario

See how many times per day planes take to the skies headed from Denver to Ontario
Sunday11daily flights
Monday10daily flights
Tuesday9daily flights
Wednesday9daily flights
Thursday9daily flights
Friday9daily flights
Saturday8daily flights

Fly with Cheapflights

What makes Cheapflights the go-to destination for all your flight needs

How does Cheapflights help users find flights from Denver to Ontario?

900+ travel sites are searched through when a user searches for a flight using Cheapflights. From the search interface, users can use filters to choose airlines, airports, flight times, cabin classes and more to their preference. Book your flight to Ontario from Denver today with Cheapflights!

Why should you use Cheapflights to find cheap flight tickets from Denver to Ontario?

It’s simple! Cheapflights, which is free to use for everyone, saves millions of users time and money every year by helping them find the cheapest and most suitable flights from Denver to Ontario.

Can Cheapflights find flights from Denver to Ontario with no change fees?

Users can book flights with no change fees policies with our dedicated filters. Book flights from Denver to Ontario flexibly with Cheapflights today.

Can Cheapflights notify me if prices for flights from Denver to Ontario become cheaper?

Yes, and it’s super simple to set up. Perform a flight search above and use a valid email address to enable the Price Alert feature. That’s it!

100% Free
Cheapflights is completely free to use, so you can start saving the moment you arrive.
Book with Flexibility
Our users can plan ahead with confidence and find flights with no change fees
Travel Smart
Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.