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Cheap flights from Ontario to Denver from £58

ONT — DEN
23 Sep — 30 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

Tue 22/913:50 -
Nonstop2h 15m
Sat 26/915:05 -
Nonstop2h 25m
Deal found 20/8£115
Wed 23/914:10 -
2 stops6h 15m
Sat 24/1005:45 -
2 stops6h 25m
Deal found 20/8£137
Mon 7/1215:50 -
1 stop4h 00m
Fri 11/1218:30 -
Nonstop2h 20m
Deal found 20/8£143
Fri 16/1012:40 -
Nonstop2h 10m
Tue 20/1008:50 -
Nonstop2h 25m
Deal found 23/8£144
Mon 14/917:15 -
1 stop4h 25m
Sat 3/1010:45 -
1 stop6h 50m
Deal found 24/8£144
Sat 10/1005:00 -
Nonstop2h 21m
Mon 12/1019:35 -
Nonstop2h 23m
Deal found 20/8£148
Mon 21/916:00 -
1 stop6h 10m
Fri 25/919:05 -
1 stop4h 00m
Deal found 19/8£150

Find flight deals from Ontario to Denver

Round-trip from

£115

One-way from

£58

Popular in

June

Cheapest in

February

Average price

£182
Southwest
  • Southwest
  • 22/9-26/9
  • Nonstop
  • 4h 40m total
  • Ontario to Denver
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United Airlines
  • United Airlines
  • 21/9
  • Nonstop
  • 2h 21m total
  • Ontario to Denver
Search Deals
Highest demand for flights based on searches. 22% potential increase in price (£35 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

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

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Fly to

Route

Depart

Return

Price

Cheapest return flight

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Fri 25/9

17:15-22:40

1 stop4h 25m

Denver Intl

Sat 26/9

08:15-12:14

1 stop4h 59m

£166
Fastest return journey

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 7/1

05:00-08:11

Nonstop2h 11m

Denver Intl

Mon 11/1

19:05-20:20

Nonstop2h 15m

£196

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Wed 30/9

14:10-21:25

2 stops6h 15m

Denver Intl

Thu 1/10

05:55-11:25

1 stop6h 30m

£207

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Tue 15/9

13:56-20:07

1 stop5h 11m

Denver Intl

Sat 19/9

13:30-18:11

1 stop5h 41m

£218

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Tue 15/9

13:56-20:07

1 stop5h 11m

Denver Intl

Wed 23/9

15:50-20:01

1 stop5h 11m

£218

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Mon 7/9

06:00-12:09

1 stop5h 09m

Denver Intl

Fri 25/9

18:06-23:47

1 stop6h 41m

£229

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Mon 12/10

05:30-11:55

2 stops5h 25m

Denver Intl

Thu 15/10

05:55-11:25

1 stop6h 30m

£252

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 24/12

05:00-08:21

Nonstop2h 21m

Denver Intl

Sun 27/12

11:16-12:42

Nonstop2h 26m

£292

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Sun 6/9

05:00-08:21

Nonstop2h 21m

Denver Intl

Tue 8/9

11:30-12:50

Nonstop2h 20m

£314

OntarioDenver

ONT Ontario - DEN Denver Intl

ONTDEN

Ontario

Thu 17/9

06:30-14:30

2 stops7h 00m

Denver Intl

Thu 24/9

16:10-21:30

2 stops6h 20m

£339

Flights are sorted by cheapest return flights first.

Deals found on 19/8

Showing 1-10 of 20 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

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 68 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 £120). Flying from Ontario to Denver in June is currently the most expensive (average of £237). 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?

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 £103 and £237 in September.
The cheapest return price found within the last 5 days was £115 on Southwest (22 Sept–26 Sept).

Related info for your journey

  • 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 14m. 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 (89%), Volaris (89%), Air Canada( 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, February is the cheapest month in which you can book a flight from Ontario to Denver (average of £120). Flying from Ontario to Denver in June is currently the most expensive (average of £237). 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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How does Cheapflights help users find flights from Ontario to Denver?

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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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