How popular is this Denver to Ontario flight route?

Flights from Denver Intl to Ontario have been viewed 71 times in the past calendar month.

What are the cheapest airlines flying from Denver to Ontario round-trip?

According to our current data, Frontier ($85), American Airlines ($197), and Delta ($217) offers the cheapest pricing from Denver to Ontario. Frontier is priced at 41% lower than the current average price of a flight leaving 3 months from now.

What are the cheapest airlines to fly from Denver to Ontario one-way?

For one-way options, check prices for Frontier. According to our data, you can fly for as low as $47. Users have also found prices from $89 and $98 on United Airlines and Alaska Airlines, respectively.

What are the cheapest flights from Denver to Ontario?

The cheapest flight price from Denver to Ontario is $46. On average you can expect to pay $146. The most popular route, (Denver Intl - Ontario), can usually be booked for $101.

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: Air Canada (89%), United Airlines (82%), Southwest( 75%).

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

Consider Frontier, United Airlines or Southwest when booking your flight. These represent the most popular airlines when flying from Denver to Ontario.

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

Monday is generally a great day to depart. Flying on this day could help you save up to 20%.

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 57 days before your planned departure. Booking around this time can save you about 73% on the cost of this flight compared to booking a flight leaving this week. We have found prices from $179 if you need a flight within two weeks. For flights within the next 72 hours, you can find tickets from as low as $363.

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

September is one of the best times of the year to fly to Ontario from Denver. Prices for September average $181 per person but you can even find prices for as low as $56. The most expensive prices can be found in the month of December. Opting for a September flight can save you 14% on your journey compared to booking in December

Most accurate provider : When it comes to deals on Denver-Ontario flights, users find the pricing of Mytrip to be most consistent on Cheapflights vs. Mytrip Users can find the same prices on Denver-Ontario flight deals on Cheapflights vs. Mytrip >95% of the time. Price accuracy is based on data collected from Denver-Ontario flight searches over the past month and is updated monthly.

Most trusted provider : When it comes to deals on Denver-Ontario flights, Cheapflights users trust Mytrip the most. Mytrip has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Denver-Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

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 3 different airlines have flights from Denver Intl (DEN) to Ontario (ONT) on a regular basis. There are 10 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 deals for flights from Denver to Ontario that include hotel bookings?

Yes. In addition to deals on Denver to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Denver to Ontario?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Denver to Ontario.

Can I find deals for business class flights from Denver to Ontario?

Yes. Cheapflights offers flight deals from Denver to Ontario by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$47+ Flights from Denver to Ontario

Home Search by date Vacation packages Hotels Flight deals Car rental Travel tips & news

Find cheap flights from Denver to Ontario with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheapflights Tip: The best prices from Denver Intl to Ontario are usually found in August or January, booked 87 days in advance, depart on a Tuesday or Saturday and return on a Saturday

Cheap flight deals from Denver to Ontario

Most accurate provider	Mytrip 3 stars
Most trusted provider	Mytrip 3 stars
Round-trip from	$85 (Cheapflightsfares)
One-way from	$47 (Cheapflightsfares)
Popular in	February
Cheapest in	August
Average price	$154
Good round-trip deal	$133 or less
Good one-way deal	$94 or less

Provider with most accurate pricing for Denver Intl-Ontario flight deals.

Search Deals

Provider most trusted by Cheapflights users for Denver Intl-Ontario flights.

Search Deals

From Denver Intl to Ontario

Search Deals

One-way flight from Denver Intl to Ontario

Search Deals

Highest demand for flights based on searches. 3% potential increase in price ($5 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 2% potential price decrease ($3 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in May 2025

Search Deals

Price to beat on a round-trip flight from Denver Intl to Ontario.

Search Deals

Price to beat on a one-way flight from Denver Intl to Ontario.

Search Deals

Find flight deals from Denver to Ontario

Cheapest flights from Denver to Ontario
Explore the most affordable flight options available from Denver to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 12, 2025.

Sat 5/1710:37 pmDEN - ONT

Nonstop2h 22mFrontier

Tue 5/2012:59 amONT - DEN

Nonstop2h 18mFrontier

Deal found 5/10

$85

Sat 6/218:42 amDEN - ONT

1 stop4h 18mAmerican Airlines

Sat 6/284:50 pmONT - DEN

1 stop3h 52mAmerican Airlines

Deal found 5/12

$197

Thu 7/37:10 amDEN - ONT

1 stop6h 07mDelta

Sun 8/31:15 pmONT - DEN

1 stop5h 40mDelta

Deal found 5/11

$227

Tue 6/36:10 amDEN - ONT

1 stop5h 50mSouthwest

Wed 6/44:30 pmONT - DEN

1 stop5h 00mSouthwest

Deal found 5/12

$254

Fri 8/157:11 pmDEN - ONT

1 stop5h 48mHawaiian Airlines

Mon 8/182:22 pmONT - DEN

1 stop8h 37mHawaiian Airlines

Deal found 5/11

$274

Thu 7/107:06 pmDEN - ONT

1 stop5h 53mAlaska Airlines

Mon 7/142:21 pmONT - DEN

1 stop8h 38mAlaska Airlines

Deal found 5/11

$277

Best flights from Denver to Ontario
Discover carefully curated flight deals from Denver to Ontario that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated May 12, 2025.

Sat 5/1710:37 pmDEN - ONT

Nonstop2h 22mFrontier

Tue 5/2012:59 amONT - DEN

Nonstop2h 18mFrontier

Deal found 5/10

$85

Sat 6/218:42 amDEN - ONT

1 stop4h 18mAmerican Airlines

Sat 6/284:50 pmONT - DEN

1 stop3h 52mAmerican Airlines

Deal found 5/12

$197

Tue 6/177:10 amDEN - ONT

1 stop6h 07mDelta

Wed 7/21:15 pmONT - DEN

1 stop5h 38mDelta

Deal found 5/11

$217

Tue 6/246:00 amDEN - ONT

1 stop9h 46mAlaska Airlines

Wed 6/254:00 pmONT - DEN

1 stop6h 59mAlaska Airlines

Deal found 5/11

$257

Wed 7/97:30 pmDEN - ONT

1 stop4h 20mSouthwest

Wed 7/2311:10 amONT - DEN

2 stops6h 15mSouthwest

Deal found 5/11

$272

Tue 6/38:02 amDEN - ONT

1 stop5h 12mUnited Airlines

Tue 6/36:32 pmONT - DEN

Nonstop2h 19mUnited Airlines

Deal found 5/11

$310

Sun 7/276:00 amDEN - ONT

1 stop8h 26mHawaiian Airlines

Tue 7/294:00 pmONT - DEN

1 stop6h 59mHawaiian Airlines

Deal found 5/12

$326

Last-minute flights from Denver to Ontario
Discover last-minute flight deals from Denver to Ontario. Data last updated May 12, 2025 and is based on user searches.

Sat 5/1710:37 pmDEN - ONT

Nonstop2h 22mFrontier

Tue 5/2012:59 amONT - DEN

Nonstop2h 18mFrontier

Deal found 5/10

$85

Sat 5/171:45 pmDEN - ONT

Nonstop2h 31mUnited Airlines

Wed 5/214:15 pmONT - DEN

Nonstop2h 20mUnited Airlines

Deal found 5/10

$317

Mon 5/197:05 pmDEN - ONT

Nonstop2h 20mSouthwest

Wed 5/215:45 amONT - DEN

Nonstop2h 10mSouthwest

Deal found 5/12

$337

Tue 5/207:05 pmDEN - ONT

1 stop5h 52mAlaska Airlines

Wed 5/2111:51 amONT - DEN

1 stop8h 47mAlaska Airlines

Deal found 5/12

$336

Wed 5/218:00 amDEN - ONT

1 stop8h 50mHawaiian Airlines

Fri 5/234:45 pmONT - DEN

1 stop6h 20mHawaiian Airlines

Deal found 5/11

$437

Tue 6/36:10 amDEN - ONT

1 stop5h 50mSouthwest

Wed 6/44:30 pmONT - DEN

1 stop5h 00mSouthwest

Deal found 5/12

$254

Tue 6/38:02 amDEN - ONT

1 stop5h 12mUnited Airlines

Tue 6/36:32 pmONT - DEN

Nonstop2h 19mUnited Airlines

Deal found 5/11

$310

Tue 6/177:10 amDEN - ONT

1 stop6h 07mDelta

Tue 7/11:15 pmONT - DEN

1 stop5h 38mDelta

Deal found 5/11

$217

Sat 6/218:42 amDEN - ONT

1 stop4h 18mAmerican Airlines

Sat 6/284:50 pmONT - DEN

1 stop3h 52mAmerican Airlines

Deal found 5/12

$197

One-way flights from Denver to Ontario
Search for one-way flight options from Denver to Ontario. Find affordable one-way fares based on user searches. Data last updated May 12, 2025.

Sun 6/810:29 pmDEN - ONT

Nonstop2h 21mFrontier

Deal found 5/12

$47

Wed 7/1611:15 amDEN - ONT

Nonstop2h 17mUnited Airlines

Deal found 5/11

$89

Wed 8/67:06 pmDEN - ONT

1 stop5h 53mAlaska Airlines

Deal found 5/11

$98

Tue 6/176:47 pmDEN - ONT

1 stop3h 51mAmerican Airlines

Deal found 5/11

$99

Wed 6/186:30 amDEN - ONT

1 stop8h 59mDelta

Deal found 5/12

$109

Thu 8/76:00 amDEN - ONT

1 stop8h 26mHawaiian Airlines

Deal found 5/11

$118

Sun 9/75:55 pmDEN - ONT

2 stops6h 30mSouthwest

Deal found 5/12

$135

Cheapflights Fare Finder

Use the filters below to find and compare flights from Denver to Ontario that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

DenverOntario

DEN - ONT

DENONT

Denver Intl

Thu 5/29

10:29 pm-11:51 pm

Nonstop2h 22m

Ontario

Sat 5/31

5:21 pm-8:45 pm

Nonstop2h 24m

$94

DenverOntario

DEN - ONT

DENONT

Denver Intl

Sat 6/21

8:42 am-12:00 pm

1 stop4h 18m

Ontario

Sat 6/28

4:50 pm-9:42 pm

1 stop3h 52m

$197

DenverOntario

DEN - ONT

DENONT

Denver Intl

Thu 7/3

7:10 am-12:17 pm

1 stop6h 07m

Ontario

Sun 8/3

1:15 pm-7:55 pm

1 stop5h 40m

$227

DenverOntario

DEN - ONT

DENONT

Denver Intl

Tue 6/3

6:10 am-11:00 am

1 stop5h 50m

Ontario

Wed 6/4

4:30 pm-10:30 pm

1 stop5h 00m

$254

DenverOntario

DEN - ONT

DENONT

Denver Intl

Sat 8/30

3:42 pm-8:33 pm

1 stop5h 51m

Ontario

Sun 8/31

1:42 pm-8:08 pm

1 stop5h 26m

$259

DenverOntario

DEN - ONT

DENONT

Denver Intl

Fri 8/15

7:11 pm-11:59 pm

1 stop5h 48m

Ontario

Mon 8/18

2:22 pm-11:59 pm

1 stop8h 37m

$274

DenverOntario

DEN - ONT

DENONT

Denver Intl

Thu 7/10

7:06 pm-11:59 pm

1 stop5h 53m

Ontario

Mon 7/14

2:21 pm-11:59 pm

1 stop8h 38m

$277

DenverOntario

DEN - ONT

DENONT

Denver Intl

Sun 6/8

10:29 pm-11:50 pm

Nonstop2h 21m

$47

DenverOntario

DEN - ONT

DENONT

Denver Intl

Wed 7/16

11:15 am-12:32 pm

Nonstop2h 17m

$89

DenverOntario

DEN - ONT

DENONT

Denver Intl

Wed 8/6

7:06 pm-11:59 pm

1 stop5h 53m

$98

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/12

Showing 1-10 of 14 results

Compare providers for flights from Denver to Ontario

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Denver to Ontario in May.

Provider	Price Accuracy	Trust Score*
Expedia	Price Accuracy1 star	Trust Score*3 stars
FlightHub	Price Accuracy3 stars	Trust Score*2 stars
eDreams	Price Accuracy3 stars	Trust Score*3 stars
Cheapflightsfares	Price Accuracy3 stars	Trust Score*2 stars
Kiwi.com	Price Accuracy3 stars	Trust Score*3 stars
Cheapfaremart	Price Accuracy-	Trust Score*1 star
Justfly.com	Price Accuracy3 stars	Trust Score*2 stars
Priceline	Price Accuracy2 stars	Trust Score*3 stars
Mytrip	Price Accuracy3 stars	Trust Score*3 stars
CheapOair	Price Accuracy3 stars	Trust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

Most accurate provider: When it comes to deals on Denver-Ontario flights, users find the pricing of Mytrip to be most consistent on Cheapflights vs. Mytrip Users can find the same prices on Denver-Ontario flight deals on Cheapflights vs. Mytrip >95% of the time. Price accuracy is based on data collected from Denver-Ontario flight searches over the past month and is updated monthly.
Most trusted provider: When it comes to deals on Denver-Ontario flights, Cheapflights users trust Mytrip the most. Mytrip has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Denver-Ontario flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

The best insider tips for Denver to Ontario flights

Cheapflights partnered with top experts to bring you the best recommendations for your Denver to Ontario trip

Airports

DEN

For a quick check-in, use the DEN Reserve to schedule your security time online, bypassing long lines at general security.

ONT

Consider renting a car at ONT for easy access to Southern California destinations like Palm Springs and Big Bear.

Our travel experts

Bill Fink

Expert on ONT

Emily Zemler

Expert on DEN

Best time to book a flight from Denver to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Denver with our price prediction graph.

Estimated round-trip price

Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

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

The price you pay for your flight from Denver to Ontario may vary depending on when you book. For the best chance of a lower fare, look to book 72 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

What is the cheapest month to book a flight from Denver to Ontario?

Currently, August is the cheapest month in which you can book a flight from Denver to Ontario (average of $246). Flying from Denver to Ontario in March is currently the most expensive (average of $328). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from DEN to 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 morning could potentially save you up to 33% on airfare.

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

Travelers seeking maximum savings on their Denver to Ontario flight should consider departing on Tuesday evenings when fares are most often at their lowest. Thursday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Denver to Ontario

The most flights from DEN to ONT are scheduled on a Monday (13 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (4 on average).

Rainfall in Ontario by month

In terms of precipitation, rainfall in Ontario ranges from 0.1 - 3.4 inches per month. February is typically the wettest month, when rainfall can reach 3.4 in. June is typically the driest time to visit Ontario when rainfall is around 0.1 in.

Temperature in Ontario by month

If weather is an important factor for your trip to Ontario, use this chart to help with planning. For those seeking warmer temperatures, August is the ideal time of year to visit, when temperatures reach an average of 78.8 F. Travelers looking to avoid the cold should look outside of December, when temperatures are typically at their lowest (around 53.6 F).

Reviews of airlines servicing Ontario

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

Alaska Airlines

8.0

Very good

10,000 reviews

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Alaska Airlines

8.0

Very good

10,000 reviews

Alaska Airlines

8.0

Very good

10,000 reviews

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Southwest

8.0

Very good

4,290 reviews

Alaska Airlines

8.0

Very good

10,000 reviews

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Delta

8.0

Very good

7,950 reviews

Alaska Airlines

8.0

Very good

10,000 reviews

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Hawaiian Airlines

7.9

Good

2,431 reviews

Alaska Airlines

8.0

Very good

10,000 reviews

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

United Airlines

7.4

Good

8,724 reviews

Alaska Airlines

8.0

Very good

10,000 reviews

Reviews

1 / 20

10.0

Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

Related info for your journey

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 3 different airlines have flights from Denver Intl (DEN) to Ontario (ONT) on a regular basis. There are 10 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.
How popular is this Denver to Ontario flight route?
Flights from Denver Intl to Ontario have been viewed 71 times in the past calendar month.
What are the cheapest airlines flying from Denver to Ontario round-trip?
According to our current data, Frontier ($85), American Airlines ($197), and Delta ($217) offers the cheapest pricing from Denver to Ontario. Frontier is priced at 41% lower than the current average price of a flight leaving 3 months from now.
What are the cheapest airlines to fly from Denver to Ontario one-way?
For one-way options, check prices for Frontier. According to our data, you can fly for as low as $47. Users have also found prices from $89 and $98 on United Airlines and Alaska Airlines, respectively.
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: Air Canada (89%), United Airlines (82%), Southwest( 75%).
What are the cheapest flights from Denver to Ontario?
The cheapest flight price from Denver to Ontario is $46. On average you can expect to pay $146. The most popular route, (Denver Intl - Ontario), can usually be booked for $101.
Can I find deals for flights from Denver to Ontario that include hotel bookings?
Yes. In addition to deals on Denver to Ontario flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Denver to Ontario?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Denver to Ontario.
Can I find deals for business class flights from Denver to Ontario?
Yes. Cheapflights offers flight deals from Denver to Ontario by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.
What is the cheapest month to book a flight from Denver to Ontario?
Currently, August is the cheapest month in which you can book a flight from Denver to Ontario (average of $246). Flying from Denver to Ontario in March is currently the most expensive (average of $328). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Browse thousands of different options on Cheapflights for your next trip

Alternative routes for Denver to Ontario

Denver to Las Vegas flights

Denver to Los Angeles flights

Denver to San Diego flights

Denver to San Francisco flights

Denver to Santa Ana flights

Denver to Reno flights

Denver to San Jose flights

Denver to Sacramento flights

Denver to Burbank flights

Denver to Santa Barbara flights

Denver to Palm Springs flights

Denver to San Luis Obispo flights

Denver to Oakland flights

Colorado Springs to Las Vegas flights

Denver to Fresno flights

Denver to Monterey flights

Denver to Medford flights

Denver to Long Beach flights

Colorado Springs to Los Angeles flights

Colorado Springs to Sacramento flights

Durango to Las Vegas flights

Colorado Springs to San Diego flights

Denver to Bakersfield flights

Denver to Santa Rosa flights

Grand Junction to Las Vegas flights

Denver to Redding flights

Colorado Springs to San Francisco flights

Denver to Arcata flights

Colorado Springs to Santa Ana flights

Aspen to San Francisco flights

Grand Junction to Los Angeles flights

Grand Junction to Sacramento flights

Colorado Springs to Ontario flights

Durango to San Diego flights

Aspen to Los Angeles flights

Durango to Santa Ana flights

Vail to Los Angeles flights

Grand Junction to San Francisco flights

Vail to Santa Ana flights

Hayden to San Francisco flights

Colorado Springs to Long Beach flights

Colorado Springs to Reno flights

Vail to San Francisco flights

Grand Junction to Santa Ana flights

Durango to Reno flights

Montrose to Los Angeles flights

Grand Junction to San Diego flights

Montrose to San Francisco flights

Complete your trip

Ontario car rentals

Los Angeles Airport car rentals

Ontario Airport car rentals

Burbank Bob Hope Airport car rentals

Long Beach Municipal Airport car rentals

Los Angeles car rentals

San Francisco car rentals

San Diego car rentals

San Jose car rentals

Fresno car rentals

Sacramento car rentals

Bakersfield car rentals

Other flights to Ontario

Top 3 airlines flying from Denver to Ontario

Airline	Cheapest	Average	Flexibility	On-time
Frontier	Cheapest$55	Average$129	FlexibilityNo cancel fee	On-time62%
Southwest	Cheapest$117	Average$243	FlexibilityNo cancel fee	On-time63%
United Airlines	Cheapest$137	Average$294	FlexibilityNo cancel fee	On-time69%

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.

$47+ Cheap flights from Denver to Ontario (DEN - ONT)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 6/8. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Denver to Ontario with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheapflights Tip: The best prices from Denver Intl to Ontario are usually found in August or January, booked 87 days in advance, depart on a Tuesday or Saturday and return on a Saturday

Cheap flight deals from Denver to Ontario

Most accurate provider

Most trusted provider

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Good round-trip deal

Good one-way deal

Find flight deals from Denver to Ontario

Cheapest flights from Denver to OntarioExplore the most affordable flight options available from Denver to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 12, 2025.

Explore the most affordable flight options available from Denver to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 12, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Denver to Ontario that are best for you.

Compare providers for flights from Denver to Ontario

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Denver to Ontario in May.

The best insider tips for Denver to Ontario flights

Cheapflights partnered with top experts to bring you the best recommendations for your Denver to Ontario trip

Airports

DEN

ONT

Our travel experts

Best time to book a flight from Denver to Ontario

Have a flexible travel schedule? Discover the best time to fly to Ontario from Denver with our price prediction graph.

Cheapflights Insights

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

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

Use this chart to determine the optimal time to book a round-trip flight from Denver to Ontario. Price data was last updated on May 9, 2025.

What is the cheapest month to book a flight from Denver to Ontario?

What is the cheapest time of day to fly from DEN to ONT?

Find hourly flight availability from Denver to Ontario. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated May 12, 2025.

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

Use this chart to determine the cheapest time to fly round-trip from Denver to Ontario. Price data was last updated on May 11, 2025.

Weekly flight availability from Denver to Ontario

Explore weekly flight availability from Denver to Ontario. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated May 12, 2025.

Rainfall in Ontario by month

Plan your trip to Ontario by taking into account the average rainfall totals by month.

Temperature in Ontario by month

Plan your trip to Ontario by taking into account the average temperature totals by month.

Reviews of airlines servicing Ontario

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

Related info for your journey

Find useful and relevant information for your journey from Denver to Ontario. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

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

How popular is this Denver to Ontario flight route?

What are the cheapest airlines flying from Denver to Ontario round-trip?

What are the cheapest airlines to fly from Denver to Ontario one-way?

What are the most reliable airlines from Denver to Ontario?

What are the cheapest flights from Denver to Ontario?

Can I find deals for flights from Denver to Ontario that include hotel bookings?

How can I find direct flights from Denver to Ontario?

Can I find deals for business class flights from Denver to Ontario?

What is the cheapest month to book a flight from Denver to Ontario?

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Denver to Ontario

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

Top 3 airlines flying from Denver to Ontario

100% Free

Book with Flexibility

Travel Smart

Cheapest flights from Denver to Ontario
Explore the most affordable flight options available from Denver to Ontario. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 12, 2025.