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Cheap flights from Ontario to Denver from £52

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 21/5. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
4 May — 11 May1
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 29 April 2025.

Round-trip from

£143

One-way from

£52

Popular in

August

Cheapest in

January

Average price

£111

Good round-trip deal

£106 or less

Good one-way deal

£85 or less
Frontier
  • Frontier
  • 12/6-19/6
  • Nonstop
  • 4h 42m total
  • Ontario to Denver
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United Airlines
  • United Airlines
  • 21/5
  • Nonstop
  • 2h 19m total
  • Ontario to Denver
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Highest demand for flights based on searches. 4% potential increase in price (£3 potential increase over avg. return price).
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Cheapest flight prices on average. 1% potential price decrease (£2 potential savings vs. average return price).
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Average for round-trip flights in April 2025
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Price to beat on a round-trip flight from Ontario to Denver Intl.
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Price to beat on a one-way flight from Ontario to Denver Intl.
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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 29 April 2025.

Thu 12/617:21ONT - DEN
Nonstop2h 21mFrontier
Thu 19/622:29DEN - ONT
Nonstop2h 21mFrontier
Deal found 28/4£143
Tue 20/516:15ONT - DEN
Nonstop2h 20mUnited Airlines
Wed 21/511:15DEN - ONT
Nonstop2h 23mUnited Airlines
Deal found 28/4£147
Wed 21/506:00ONT - DEN
1 stop6h 58mAlaska Airlines
Wed 28/519:05DEN - ONT
1 stop5h 52mAlaska Airlines
Deal found 28/4£155
Wed 11/617:08ONT - DEN
1 stop4h 17mDelta
Wed 25/607:10DEN - ONT
1 stop6h 07mDelta
Deal found 27/4£162
Sat 28/615:00ONT - DEN
1 stop6h 30mSouthwest
Sat 5/709:00DEN - ONT
Nonstop2h 15mSouthwest
Deal found 28/4£186
Sat 17/511:51ONT - DEN
1 stop8h 47mHawaiian Airlines
Sat 23/811:40DEN - ONT
1 stop6h 20mHawaiian Airlines
Deal found 29/4£231
Thu 15/513:15ONT - DEN
1 stop3h 52mAmerican Airlines
Thu 22/511:16DEN - ONT
1 stop5h 33mAmerican Airlines
Deal found 28/4£282

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 29 April 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 12/6

17:21-20:42

Nonstop2h 21m

Denver Intl

Thu 19/6

22:29-23:50

Nonstop2h 21m

£143

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 20/5

16:15-19:35

Nonstop2h 20m

Denver Intl

Wed 21/5

11:15-12:38

Nonstop2h 23m

£147

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 21/5

06:00-13:58

1 stop6h 58m

Denver Intl

Wed 28/5

19:05-23:57

1 stop5h 52m

£155

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 11/6

09:44-15:00

1 stop4h 16m

Denver Intl

Tue 24/6

18:23-23:46

1 stop6h 23m

£162

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 28/6

15:00-22:30

1 stop6h 30m

Denver Intl

Sat 5/7

09:00-10:15

Nonstop2h 15m

£186

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 17/5

11:51-21:38

1 stop8h 47m

Denver Intl

Sat 23/8

11:40-17:00

1 stop6h 20m

£231

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 15/5

13:15-18:07

1 stop3h 52m

Denver Intl

Thu 22/5

11:16-15:49

1 stop5h 33m

£282

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 21/5

05:05-08:24

Nonstop2h 19m

£52

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 21/5

16:10-23:00

1 stop5h 50m

£59

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 28/5

16:45-00:05

1 stop6h 20m

£81

Flights are sorted by cheapest return flights first.

Deals found on 28/4

Showing 1-10 of 13 results
1
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.

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 25 April 2025.

Booking 55 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 29 April 2025.

It’s optimal to fly from Ontario to Denver in the afternoon. By choosing this option you can save up to 65% 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 29 April 2025.

The most flights from ONT to DEN are scheduled on a Monday (12 on average). You will have fewer flight options on Thursday, which is when the least amount of flights are scheduled (10 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 29 April 2025.
Read through reviews of airlines operating flights from Ontario to Denver, such as Alaska Airlines, Southwest and Delta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Crew

8.5

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very Good
9,961 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Crew

8.5

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very Good
4,295 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Crew

8.5

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very Good
7,929 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Crew

8.5

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.9
Good
2,402 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Crew

8.5

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,696 reviews
Alaska Airlines
8.0
Very Good
9,961 reviews
Check prices

Crew

8.5

Food

7.1

Comfort

7.9

Boarding

8.2

Entertainment

7.1

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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 9 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 Frontier is currently your cheapest option to Denver, with prices starting at £143. Additional return tickets that might be worth considering are offered by United Airlines and Alaska Airlines, with the lowest prices starting at £147 and £155, respectively.

  • 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 United Airlines (£52), Southwest (£59), and Alaska Airlines (£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: SkyWest Airlines (100%), United Airlines (88%), Southwest( 86%).

  • What are the cheapest flights from Ontario to Denver?

    On average you can expect to pay £101 for a flight from Ontario to Denver. The cheapest flight overall is £77 while the most popular route, (Ontario - Denver Intl) is currently priced at £144.

  • 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

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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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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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