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Cheap flights from Ontario to Denver from £38

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 22/4. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
27 Mar — 3 Apr1
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 22 March 2025.

Round-trip from

£75

One-way from

£38

Popular in

March

Cheapest in

January

Average price

£135
Southwest
  • Southwest
  • 1/5-6/5
  • Nonstop
  • 4h 30m total
  • Ontario to Denver
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Southwest
  • Southwest
  • 22/4
  • Nonstop
  • 2h 10m total
  • Ontario to Denver
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High demand for flights, 10% potential price rise
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Cheapest flight prices on average. 2% potential price decrease (£2 potential savings vs. average return price).
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Average for round-trip flights in March 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 22 March 2025.

Thu 1/505:35ONT - DEN
Nonstop2h 10mSouthwest
Tue 6/508:25DEN - ONT
Nonstop2h 20mSouthwest
Deal found 21/3£75
Thu 1/505:05ONT - DEN
Nonstop2h 19mUnited Airlines
Sat 3/511:15DEN - ONT
Nonstop2h 23mUnited Airlines
Deal found 22/3£121
Sun 20/407:00ONT - DEN
1 stop6h 53mHawaiian Airlines
Tue 22/414:39DEN - ONT
1 stop6h 50mHawaiian Airlines
Deal found 21/3£136
Thu 1/516:29ONT - DEN
1 stop6h 30mAlaska Airlines
Sat 3/507:00DEN - ONT
1 stop9h 32mAlaska Airlines
Deal found 21/3£167
Fri 18/417:15ONT - DEN
1 stop4h 11mDelta
Sun 20/407:00DEN - ONT
1 stop6h 16mDelta
Deal found 22/3£168
Mon 1/913:00ONT - DEN
Nonstop2h 14mMultiple Airlines
Fri 5/911:36DEN - ONT
1 stop6h 34mMultiple Airlines
Deal found 21/3£438

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 22 March 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 1/5

05:05-08:24

Nonstop2h 19m

Denver Intl

Mon 5/5

13:45-15:09

Nonstop2h 24m

£75

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Fri 18/4

06:20-12:15

1 stop4h 55m

Denver Intl

Tue 22/4

18:45-20:05

Nonstop2h 20m

£98

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sun 20/4

07:00-14:53

1 stop6h 53m

Denver Intl

Tue 22/4

14:39-20:29

1 stop6h 50m

£136

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Thu 1/5

16:29-23:59

1 stop6h 30m

Denver Intl

Sat 3/5

07:00-15:32

1 stop9h 32m

£167

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Fri 18/4

17:15-22:26

1 stop4h 11m

Denver Intl

Sun 20/4

07:00-12:16

1 stop6h 16m

£168

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Mon 1/9

13:00-16:14

Nonstop2h 14m

Denver Intl

Fri 5/9

11:36-17:10

1 stop6h 34m

£438

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Tue 22/4

05:45-08:55

Nonstop2h 10m

£38

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 12/4

05:00-08:19

Nonstop2h 19m

£60

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 23/4

16:29-23:59

1 stop6h 30m

£68

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Mon 21/4

06:00-12:56

1 stop5h 56m

£84

Flights are sorted by cheapest return flights first.

Deals found on 22/3

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 21 March 2025.

Booking 53 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 22 March 2025.

It’s optimal to fly from Ontario to Denver in the morning. By choosing this option you can save up to 34% 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 22 March 2025.

The most flights from ONT to DEN are scheduled on a Thursday (12 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (6 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 22 March 2025.
Read through reviews of airlines operating flights from Ontario to Denver, such as Southwest, Alaska Airlines and Delta. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very Good
4,277 reviews
Check prices

Boarding

8.2

Entertainment

7.6

Comfort

8.1

Overall

8.1

Crew

8.7

Food

7.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Southwest
8.1
Very Good
4,277 reviews
Southwest
8.1
Very Good
4,277 reviews
Check prices

Boarding

8.2

Entertainment

7.6

Comfort

8.1

Overall

8.1

Crew

8.7

Food

7.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Alaska Airlines
8.0
Very Good
9,768 reviews
Southwest
8.1
Very Good
4,277 reviews
Check prices

Boarding

8.2

Entertainment

7.6

Comfort

8.1

Overall

8.1

Crew

8.7

Food

7.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Delta
8.0
Very Good
7,892 reviews
Southwest
8.1
Very Good
4,277 reviews
Check prices

Boarding

8.2

Entertainment

7.6

Comfort

8.1

Overall

8.1

Crew

8.7

Food

7.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
Hawaiian Airlines
7.9
Good
2,325 reviews
Southwest
8.1
Very Good
4,277 reviews
Check prices

Boarding

8.2

Entertainment

7.6

Comfort

8.1

Overall

8.1

Crew

8.7

Food

7.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.
United Airlines
7.4
Good
8,605 reviews
Southwest
8.1
Very Good
4,277 reviews
Check prices

Boarding

8.2

Entertainment

7.6

Comfort

8.1

Overall

8.1

Crew

8.7

Food

7.1

Reviews

1 / 20
10.0
Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.

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 United Airlines is currently your cheapest option to Denver, with prices starting at £75. Additional return tickets that might be worth considering are offered by Southwest and Hawaiian Airlines, with the lowest prices starting at £98 and £136, respectively. United Airlines is priced at 30% lower than the current average price of a flight leaving 3 months from now.

  • 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 Southwest (£38), United Airlines (£60), and Alaska Airlines (£68).

  • 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: United Airlines (88%), Air Canada (88%), Southwest( 86%).

  • 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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Fly with Cheapflights

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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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