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Cheap flights from Ontario to Denver from £58

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 11/9. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
12 Sep — 19 Sep1
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 13 August 2026.

Sun 6/910:50 -
Nonstop2h 10m
Fri 11/912:45 -
Nonstop2h 15m
Deal found 8/8£116
Sat 5/915:15 -
1 stop4h 00m
Sun 6/908:50 -
Nonstop2h 15m
Deal found 11/8£124
Sun 6/906:00 -
Nonstop2h 24m
Fri 11/913:48 -
1 stop6h 48m
Deal found 10/8£126
Sat 5/913:18 -
Nonstop2h 21m
Sun 6/919:30 -
Nonstop2h 23m
Deal found 10/8£128
Sat 5/913:06 -
1 stop5h 55m
Sun 6/907:05 -
1 stop6h 11m
Deal found 11/8£169
Fri 11/913:15 -
1 stop5h 55m
Sat 12/912:55 -
2 stops6h 30m
Deal found 12/8£182
Wed 28/1008:25 -
2 stops5h 50m
Fri 30/1005:55 -
1 stop6h 30m
Deal found 9/8£183

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 13 August 2026.

Round-trip from

£116

One-way from

£58

Popular in

June

Cheapest in

February

Average price

£153
Southwest
  • Southwest
  • 6/9-11/9
  • Nonstop
  • 4h 25m total
  • Ontario to Denver
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United Airlines
  • United Airlines
  • 11/9
  • Nonstop
  • 2h 21m total
  • Ontario to Denver
Search Deals
Highest demand for flights based on searches. 24% potential increase in price (£38 potential increase over avg. return price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease (£6 potential savings vs. average return price).
Search Deals
Average for round-trip flights in August 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 13 August 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 Ontario - DEN Denver Intl

ONTDEN

Ontario

Sat 24/10

05:00-08:21

Nonstop2h 21m

Denver Intl

Mon 26/10

19:25-20:51

Nonstop2h 26m

£201

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Sat 12/9

07:12-18:32

1 stop10h 20m

Denver Intl

Sat 19/9

08:22-16:10

2 stops8h 48m

£264
Fastest return journey

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 14/1

05:00-08:11

Nonstop2h 11m

Denver Intl

Tue 9/2

11:15-12:33

Nonstop2h 18m

£275

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 7/1

13:00-16:14

Nonstop2h 14m

Denver Intl

Mon 11/1

19:05-20:20

Nonstop2h 15m

£281

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Sun 25/10

07:10-12:30

1 stop4h 20m

Denver Intl

Tue 27/10

14:55-21:15

2 stops7h 20m

£295

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 31/12

13:18-20:28

1 stop6h 10m

Denver Intl

Sun 31/1

13:25-17:47

1 stop5h 22m

£295

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Fri 11/9

05:00-08:21

Nonstop2h 21m

Denver Intl

Mon 14/9

11:30-12:50

Nonstop2h 20m

£296

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Tue 25/8

14:10-21:20

2 stops6h 10m

Denver Intl

Fri 28/8

10:15-15:05

2 stops5h 50m

£316

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 27/8

05:00-08:21

Nonstop2h 21m

Denver Intl

Sun 30/8

19:30-20:53

Nonstop2h 23m

£318

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 7/1

12:00-22:40

1 stop9h 40m

Denver Intl

Mon 11/1

19:04-17:12

2 stops23h 08m

£329

Flights are sorted by cheapest return flights first.

Deals found on 8/8

Showing 1-10 of 21 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?

Booking 71 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, February is the cheapest month in which you can book a flight from Ontario to Denver (average of £123). Flying from Ontario to Denver in June is currently the most expensive (average of £239). 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 13 August 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.

How much does it cost for a return flight from Ontario to Denver?

Airfare is typical for this route at the moment.

Ontario to Denver flights typically cost between £115 and £214 in September.
The cheapest return price found within the last 5 days was £116 on Southwest (6 Sept–11 Sept).

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 2 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 21m. 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: Frontier (92%), Volaris (92%), Air Canada( 76%).

  • 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, February is the cheapest month in which you can book a flight from Ontario to Denver (average of £123). Flying from Ontario to Denver in June is currently the most expensive (average of £239). 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

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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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