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Cheap flights from Ontario to Denver from £66

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 9/5. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
10 Apr — 17 Apr1
1 adult
1 adult, Economy, 0 bags

Cheap flight deals from Ontario to Denver

Enter your travel dates to find the best prices.

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 11 March 2026.

Sun 5/406:20
ONT
-
DEN
Nonstop2h 23m
Frontier
Sun 12/422:30
DEN
-
ONT
1 stop10h 34m
Frontier
Deal found 6/3£120
Wed 15/410:40
ONT
-
DEN
Nonstop2h 15m
Southwest
Sat 18/420:00
DEN
-
ONT
Nonstop2h 20m
Southwest
Deal found 9/3£132
Wed 29/411:53
ONT
-
DEN
1 stop10h 57m
Delta
Sat 2/519:45
DEN
-
ONT
1 stop16h 28m
Delta
Deal found 7/3£138
Tue 28/411:53
ONT
-
DEN
1 stop23h 24m
Delta
Wed 6/508:10
DEN
-
ONT
2 stops10h 05m
Delta
Deal found 7/3£141
Wed 27/513:55
ONT
-
DEN
Nonstop2h 15m
Southwest
Wed 3/606:45
DEN
-
ONT
2 stops5h 50m
Southwest
Deal found 9/3£143
Wed 15/413:34
ONT
-
DEN
Nonstop2h 22m
United Airlines
Sat 18/411:21
DEN
-
ONT
1 stop7h 26m
United Airlines
Deal found 6/3£145
Tue 7/410:40
ONT
-
DEN
Nonstop2h 15m
Southwest
Tue 14/408:55
DEN
-
ONT
Nonstop2h 20m
Southwest
Deal found 10/3£148
Thu 2/414:50
ONT
-
DEN
Nonstop2h 10m
Southwest
Mon 6/418:20
DEN
-
ONT
Nonstop2h 25m
Southwest
Deal found 10/3£150

Find 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 11 March 2026.

Round-trip from

£120

One-way from

£66

Popular in

March

Cheapest in

August

Average price

£172
Frontier
  • Frontier
  • 5/4-12/4
  • 1 total stop
  • 12h 57m total
  • Ontario to Denver
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United Airlines
  • United Airlines
  • 9/5
  • Nonstop
  • 2h 22m total
  • Ontario to Denver
Search Deals
Highest demand for flights based on searches. 1% potential increase in price (£1 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease (£3 potential savings vs. average return price).
Search Deals
Average for round-trip flights in March 2026
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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 11 March 2026.
Use the filters below to find and compare flights from Ontario to Denver that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest return flight

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 23/5

13:29-19:52

1 stop5h 23m

Denver Intl

Tue 26/5

06:05-12:35

1 stop7h 30m

£164

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Fri 10/4

15:55-23:05

1 stop6h 10m

Denver Intl

Wed 15/4

06:45-11:35

2 stops5h 50m

£189

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 14/4

05:10-08:32

Nonstop2h 22m

Denver Intl

Wed 22/4

13:40-17:47

1 stop5h 07m

£200

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 31/3

17:09-22:31

1 stop4h 22m

Denver Intl

Thu 2/4

18:15-23:51

1 stop6h 36m

£208

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 4/6

05:00-08:20

Nonstop2h 20m

Denver Intl

Tue 9/6

07:40-12:12

1 stop5h 32m

£209
Fastest return journey

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 2/5

05:00-08:22

Nonstop2h 22m

Denver Intl

Mon 4/5

19:10-20:36

Nonstop2h 26m

£210

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 25/4

05:30-12:20

2 stops5h 50m

Denver Intl

Mon 27/4

18:25-23:05

1 stop5h 40m

£211

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 5/5

06:00-16:02

1 stop9h 02m

Denver Intl

Wed 6/5

08:00-23:48

2 stops16h 48m

£224

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 31/3

05:10-08:32

Nonstop2h 22m

Denver Intl

Thu 9/4

19:10-20:36

Nonstop2h 26m

£228

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 2/4

05:10-08:32

Nonstop2h 22m

Denver Intl

Mon 6/4

19:10-20:36

Nonstop2h 26m

£228

Flights are sorted by cheapest return flights first.

Deals found on 8/3

Showing 1-10 of 22 resultsSorted by cheapest first
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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 6 March 2026.

Booking 51 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, August is the cheapest month in which you can book a flight from Ontario to Denver (average of £33). Flying from Ontario to Denver in September is currently the most expensive (average of £56). 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 11 March 2026.

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 3 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 22m. 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: Volaris (96%), Frontier (95%), Air Canada( 88%).

  • 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, August is the cheapest month in which you can book a flight from Ontario to Denver (average of £33). Flying from Ontario to Denver in September is currently the most expensive (average of £56). 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

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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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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.

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