Find flights
Deals
When to book
Airlines
FAQs

Cheap flights from Ontario to Denver from £39

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 12/5. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
26 Feb — 5 Mar1
1 adult

Cheap flight deals from Ontario to Denver

Discover tips and strategies to find the most affordable flight options for your journey from Ontario (ONT) to Denver (DEN). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated 21 February 2025.

Round-trip from

£77

One-way from

£39

Popular in

August

Cheapest in

January

Average price

£119
Southwest
  • Southwest
  • 24/4-29/4
  • Nonstop
  • 4h 30m total
  • Ontario to Denver
Search Deals
Southwest
  • Southwest
  • 12/5
  • Nonstop
  • 2h 10m total
  • Ontario to Denver
Search Deals
Highest demand for flights based on searches. 5% potential increase in price (£4 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease (£2 potential savings vs. average return price).
Search Deals
Average for round-trip flights in February 2025
Search Deals

Find flight deals from Ontario to Denver

Cheapest flights from Ontario to Denver
Explore the most affordable flight options available from Ontario to Denver. Find the lowest fares from popular airlines and budget airlines, with prices last updated on 21 February 2025.

Thu 24/405:35ONT - DEN
Nonstop2h 10mSouthwest
Mon 28/421:40DEN - ONT
Nonstop2h 20mSouthwest
Deal found 20/2£77
Thu 3/406:00ONT - DEN
1 stop6h 00mDelta
Tue 8/414:20DEN - ONT
1 stop9h 03mDelta
Deal found 21/2£166
Mon 17/307:00ONT - DEN
1 stop5h 54mAlaska Airlines
Tue 25/314:53DEN - ONT
1 stop10h 06mAlaska Airlines
Deal found 20/2£171
Wed 26/313:40ONT - DEN
Nonstop2h 20mUnited Airlines
Mon 31/319:19DEN - ONT
Nonstop2h 23mUnited Airlines
Deal found 20/2£204

Find flights from Ontario to Denver within your budget

Customise your flight search to find flights from Ontario to Denver that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 858,174 searches. Data last updated 21 February 2025.

Fly from

Ontario

Fly to

Denver

Route

Depart

Return

Price

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 24/4

05:35-08:45

Nonstop2h 10m

Denver Intl

Mon 28/4

21:40-23:00

Nonstop2h 20m

£77

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 3/4

06:00-13:00

1 stop6h 00m

Denver Intl

Tue 8/4

14:20-22:23

1 stop9h 03m

£166

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Mon 17/3

07:00-13:54

1 stop5h 54m

Denver Intl

Tue 25/3

14:53-23:59

1 stop10h 06m

£171

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 26/3

13:40-17:00

Nonstop2h 20m

Denver Intl

Mon 31/3

19:19-20:42

Nonstop2h 23m

£204

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Mon 12/5

16:15-19:35

Nonstop2h 20m

£39

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 22/5

15:15-18:30

Nonstop2h 15m

£55

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 18/3

05:40-13:29

1 stop6h 49m

£81

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Mon 7/4

06:55-13:53

1 stop5h 58m

£86

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 11/3

06:00-16:12

1 stop9h 12m

£117

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Fri 30/5

22:40-11:54

1 stop12h 14m

£211

Flights are sorted by cheapest return flights first.

Deals found on 21/2

Best time to book a flight from Ontario to Denver

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

Travel insights for flights from Ontario to Denver

Get recent, data-driven insights about flights from Ontario to Denver including ideal travel times, pricing trends, and more.

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

Use this chart to determine the optimal time to book a return flight from Ontario to Denver. Price data was last updated on 14 February 2025.

Booking 47 days in advance of your planned departure date is, on average, the best time to get cheap flights from Ontario to Denver. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

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

Currently, January is the cheapest month in which you can book a flight from Ontario to Denver (average of £667). Flying from Ontario to Denver in July is currently the most expensive (average of £1,030). 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 ONT to DEN?

Find hourly flight availability from Ontario to Denver. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated 21 February 2025.

It’s optimal to fly from Ontario to Denver in the morning. By choosing this option you can save up to 17% on the cost of your flight, compared to a flight at midday.

Weekly flight availability from Ontario to Denver

Explore weekly flight availability from Ontario to Denver. 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 21 February 2025.

The most flights from ONT to DEN are scheduled on a Thursday (15 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (5 on average).

Rainfall in Denver by month

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

In terms of precipitation, rainfall in Denver ranges from 13.0 - 58.0 inches per month. May is typically the wettest month, when rainfall can reach 58.0 mm. January is typically the driest time to visit Denver when rainfall is around 13.0 mm.

Temperature in Denver by month

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

If weather is an important factor for your trip to Denver, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 23.0 C. Travellers hoping to avoid the cold should look outside of January, when temperatures are typically at their lowest (around -1.0 C).

Reviews of airlines servicing Denver

Get insights into the airlines that provide service to Denver. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Denver. Reviews last updated 21 February 2025.
Read through reviews of airlines operating flights from Ontario to Denver, such as Southwest, Alaska Airlines and Delta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very Good
4,406 reviews
Check prices

Comfort

8.1

Boarding

8.2

Entertainment

7.6

Food

7.1

Overall

8.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Steven,Feb 2025

BZN - DEN

Bozeman Airport knows how to deal with snow. I saw many airlines leave with only small delays due to the foot of snow. Our plane was 4 hours delayed. I missed my connection in Denver with a 3.5 hour layover. Because of that, the best you Southwest could do was make me wait more hours, them send me to Chicago Midway, where I had to wait overnight, for 7 more hours until a flight to RSW was available. Nobody at Southwest told me that Midway shuts down after 8pm. Everything was closed. I had no idea. You just dumped me there. I am a 65 year old man and you dumped me in Midway without even a couch to lie on. I was awake 21 hours because of this. No, it was not an act of God. Other airlines were moving passengers out. It was incompetence Shame on you.

Southwest
8.1
Very Good
4,406 reviews
Southwest
8.1
Very Good
4,406 reviews
Check prices

Comfort

8.1

Boarding

8.2

Entertainment

7.6

Food

7.1

Overall

8.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Steven,Feb 2025

BZN - DEN

Bozeman Airport knows how to deal with snow. I saw many airlines leave with only small delays due to the foot of snow. Our plane was 4 hours delayed. I missed my connection in Denver with a 3.5 hour layover. Because of that, the best you Southwest could do was make me wait more hours, them send me to Chicago Midway, where I had to wait overnight, for 7 more hours until a flight to RSW was available. Nobody at Southwest told me that Midway shuts down after 8pm. Everything was closed. I had no idea. You just dumped me there. I am a 65 year old man and you dumped me in Midway without even a couch to lie on. I was awake 21 hours because of this. No, it was not an act of God. Other airlines were moving passengers out. It was incompetence Shame on you.

Alaska Airlines
8.0
Very Good
9,696 reviews
Southwest
8.1
Very Good
4,406 reviews
Check prices

Comfort

8.1

Boarding

8.2

Entertainment

7.6

Food

7.1

Overall

8.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Steven,Feb 2025

BZN - DEN

Bozeman Airport knows how to deal with snow. I saw many airlines leave with only small delays due to the foot of snow. Our plane was 4 hours delayed. I missed my connection in Denver with a 3.5 hour layover. Because of that, the best you Southwest could do was make me wait more hours, them send me to Chicago Midway, where I had to wait overnight, for 7 more hours until a flight to RSW was available. Nobody at Southwest told me that Midway shuts down after 8pm. Everything was closed. I had no idea. You just dumped me there. I am a 65 year old man and you dumped me in Midway without even a couch to lie on. I was awake 21 hours because of this. No, it was not an act of God. Other airlines were moving passengers out. It was incompetence Shame on you.

Delta
8.0
Very Good
8,217 reviews
Southwest
8.1
Very Good
4,406 reviews
Check prices

Comfort

8.1

Boarding

8.2

Entertainment

7.6

Food

7.1

Overall

8.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Steven,Feb 2025

BZN - DEN

Bozeman Airport knows how to deal with snow. I saw many airlines leave with only small delays due to the foot of snow. Our plane was 4 hours delayed. I missed my connection in Denver with a 3.5 hour layover. Because of that, the best you Southwest could do was make me wait more hours, them send me to Chicago Midway, where I had to wait overnight, for 7 more hours until a flight to RSW was available. Nobody at Southwest told me that Midway shuts down after 8pm. Everything was closed. I had no idea. You just dumped me there. I am a 65 year old man and you dumped me in Midway without even a couch to lie on. I was awake 21 hours because of this. No, it was not an act of God. Other airlines were moving passengers out. It was incompetence Shame on you.

Hawaiian Airlines
7.9
Good
2,317 reviews
Southwest
8.1
Very Good
4,406 reviews
Check prices

Comfort

8.1

Boarding

8.2

Entertainment

7.6

Food

7.1

Overall

8.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Steven,Feb 2025

BZN - DEN

Bozeman Airport knows how to deal with snow. I saw many airlines leave with only small delays due to the foot of snow. Our plane was 4 hours delayed. I missed my connection in Denver with a 3.5 hour layover. Because of that, the best you Southwest could do was make me wait more hours, them send me to Chicago Midway, where I had to wait overnight, for 7 more hours until a flight to RSW was available. Nobody at Southwest told me that Midway shuts down after 8pm. Everything was closed. I had no idea. You just dumped me there. I am a 65 year old man and you dumped me in Midway without even a couch to lie on. I was awake 21 hours because of this. No, it was not an act of God. Other airlines were moving passengers out. It was incompetence Shame on you.

JetBlue
7.4
Good
3,069 reviews
Southwest
8.1
Very Good
4,406 reviews
Check prices

Comfort

8.1

Boarding

8.2

Entertainment

7.6

Food

7.1

Overall

8.1

Crew

8.7

Reviews

1 / 20

2.0
Mediocre

Steven,Feb 2025

BZN - DEN

Bozeman Airport knows how to deal with snow. I saw many airlines leave with only small delays due to the foot of snow. Our plane was 4 hours delayed. I missed my connection in Denver with a 3.5 hour layover. Because of that, the best you Southwest could do was make me wait more hours, them send me to Chicago Midway, where I had to wait overnight, for 7 more hours until a flight to RSW was available. Nobody at Southwest told me that Midway shuts down after 8pm. Everything was closed. I had no idea. You just dumped me there. I am a 65 year old man and you dumped me in Midway without even a couch to lie on. I was awake 21 hours because of this. No, it was not an act of God. Other airlines were moving passengers out. It was incompetence Shame on you.

Related info for your journey

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

  • How popular is this Ontario to Denver flight route?

    The Ontario to Denver Intl flight path was viewed by 10 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

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

    Flying on Southwest is currently your cheapest option to Denver, with prices starting at £77. Additional return tickets that might be worth considering are offered by Delta and Alaska Airlines, with the lowest prices starting at £166 and £171, respectively. Southwest is priced at 32% lower than the current average price of a flight leaving 3 months from now.

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

    The cheapet airlines for a one-way flight from Ontario to Denver are Southwest (£39), United Airlines (£63), and Delta (£81).

  • What are the most reliable airlines from Ontario to Denver?

    Before booking your flight to Denver from Ontario, check out the most reliable airlines to get you to your destination on time: United Airlines (93%), Air Canada (91%), Frontier( 78%).

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

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

  • How can I find direct flights from Ontario to Denver?

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

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

    Yes. Cheapflights offers flight deals from Ontario to Denver 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 Ontario to Denver?

    Currently, January is the cheapest month in which you can book a flight from Ontario to Denver (average of £667). Flying from Ontario to Denver in July is currently the most expensive (average of £1,030). 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

Travelling to a place near Ontario?

Book flights to Ontario if you plan to visit one of these locations
Winter Park
Frisco

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 Ontario to Denver

See prices for flight routes from nearby airports that may be better suited for you.
Los Angeles to Denver flights
Santa Ana to Denver flights
San Diego to Denver flights
San Francisco to Denver flights

Fly with Cheapflights

Find the best flight deals on Cheapflights, where travellers can enjoy low prices and a wide availability of flights to their desired destinations.

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

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 Denver from Ontario today with Cheapflights!

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

Cheapflights helps you find that perfect flight to Denver from Ontario by searching from hundreds of airlines and agencies you know and love. We are also free to use, in case you were wondering!

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

Cheapflights does show flights with no change fees to all users. To see these options for flights from Ontario to Denver, users can toggle the no change fees filter when performing a flight search.

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

Not ready to book yet? You can track prices for flights from Ontario to Denver on Cheapflights with our Price Alert feature and get notified when better prices are available.

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.