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Cheap flights from Ontario to Denver from £49

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 25/11. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
16 Oct — 23 Oct1
1 adult
1 adult, Economy

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 16 September 2025.

Round-trip from

£96

One-way from

£49

Popular in

June

Cheapest in

January

Average price

£116
United Airlines
  • United Airlines
  • 25/11-29/11
  • Nonstop
  • 4h 37m total
  • Ontario to Denver
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United Airlines
  • United Airlines
  • 13/1
  • Nonstop
  • 2h 19m total
  • Ontario to Denver
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Highest demand for flights based on searches. 16% potential increase in price (£16 potential increase over avg. return price).
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Cheapest flight prices on average. 4% potential price decrease (£4 potential savings vs. average return price).
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Average for round-trip flights in September 2025
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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 16 September 2025.

Tue 25/1105:05ONT - DEN
Nonstop2h 14mUnited Airlines
Sat 29/1123:59DEN - ONT
Nonstop2h 23mUnited Airlines
Deal found 14/9£96
Fri 19/1205:05ONT - DEN
Nonstop2h 19mUnited Airlines
Fri 26/1219:43DEN - ONT
Nonstop2h 24mUnited Airlines
Deal found 14/9£105
Thu 25/1211:15ONT - DEN
Nonstop2h 10mSouthwest
Tue 30/1222:45DEN - ONT
Nonstop2h 20mSouthwest
Deal found 15/9£106
Fri 17/1005:05ONT - DEN
Nonstop2h 17mUnited Airlines
Fri 17/1016:05DEN - ONT
Nonstop2h 18mUnited Airlines
Deal found 15/9£108
Sat 22/1118:15ONT - DEN
1 stop4h 35mSouthwest
Thu 27/1113:10DEN - ONT
Nonstop2h 20mSouthwest
Deal found 13/9£113
Wed 15/1011:00ONT - DEN
2 stops6h 20mSouthwest
Sat 18/1007:45DEN - ONT
1 stop6h 15mSouthwest
Deal found 14/9£115
Thu 9/1016:20ONT - DEN
Nonstop2h 10mSouthwest
Mon 13/1022:25DEN - ONT
Nonstop2h 15mSouthwest
Deal found 15/9£116
Fri 24/1014:15ONT - DEN
Nonstop2h 10mSouthwest
Mon 27/1022:25DEN - ONT
Nonstop2h 15mSouthwest
Deal found 14/9£118
Thu 23/1017:55ONT - DEN
1 stop4h 15mSouthwest
Sat 25/1013:55DEN - ONT
2 stops7h 55mSouthwest
Deal found 15/9£124
Wed 29/1011:00ONT - DEN
2 stops6h 05mSouthwest
Sun 2/1105:25DEN - ONT
1 stop6h 00mSouthwest
Deal found 13/9£127

Cheapflights Fare Finder

 
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 16 September 2025.
Use the filters below to find and compare flights from Ontario to Denver that are best for you.

Fly from

Ontario

Fly to

Denver

Route

Depart

Return

Price

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 9/10

16:20-19:30

Nonstop2h 10m

Denver Intl

Mon 13/10

22:25-23:40

Nonstop2h 15m

£116

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 23/10

17:55-23:10

1 stop4h 15m

Denver Intl

Sat 25/10

13:55-20:50

2 stops7h 55m

£124

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 28/2

06:00-16:24

1 stop9h 24m

Denver Intl

Sat 7/3

11:30-16:53

1 stop6h 23m

£135

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 11/12

05:05-08:20

Nonstop2h 15m

Denver Intl

Tue 16/12

11:15-12:32

Nonstop2h 17m

£148

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 27/11

05:05-08:19

Nonstop2h 14m

Denver Intl

Sun 30/11

23:59-01:22

Nonstop2h 23m

£148

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 23/12

05:05-08:24

Nonstop2h 19m

Denver Intl

Mon 29/12

19:43-21:07

Nonstop2h 24m

£148

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Fri 26/12

05:05-08:24

Nonstop2h 19m

Denver Intl

Mon 29/12

11:15-12:38

Nonstop2h 23m

£148

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sun 7/12

05:05-08:20

Nonstop2h 15m

Denver Intl

Sat 13/12

19:20-20:42

Nonstop2h 22m

£148

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 23/12

05:05-08:24

Nonstop2h 19m

Denver Intl

Wed 31/12

19:43-21:07

Nonstop2h 24m

£148

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sun 7/12

05:05-08:20

Nonstop2h 15m

Denver Intl

Tue 16/12

11:15-12:32

Nonstop2h 17m

£148

Flights are sorted by cheapest return flights first.

Deals found on 15/9

Showing 1-10 of 22 results
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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.

Cheapflights Insights

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

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 12 September 2025.

Booking 41 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 £983). 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 16 September 2025.

It’s optimal to fly from Ontario to Denver in the evening. By choosing this option you can save up to 85% on the cost of your flight, compared to a flight at midday.

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 8 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • How long is the flight from Ontario to Denver?

    Departing from Ontario to Denver will take you 2h 10m. There are 817 mi between Ontario and Denver. When browsing for deals, the options you’ll see will be for both direct flights and flights with stops.

  • 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: Air Canada (73%), United Airlines (71%), Southwest( 66%).

  • 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 £983). 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 Denver?

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

Browse thousands of different options on Cheapflights for your next trip

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Alternative routes for Ontario to Denver

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

Fly with Cheapflights

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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.

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