Cheap Flights from Ontario to Denver

Cheapest flights from Ontario to Denver

Flaut.Travel was designed and developed by a team dedicated to making the process of searching, comparing and booking airline tickets as easy and convenient as possible. Our service helps travelers to find and buy the cheapest flights from Ontario to Denver. We have connected more than 40 airlines and airline ticketing agencies to help you find the most suitable and affordable flight option.

Cheapest one way flight

$34

Frontier Airlines

Direct flight

2h 25m

08/19/2026

The cheapest one-way flight from Ontario to Denver departs on 08/19/2026, is operated by Frontier Airlines and costs $34

Cheapest round trip flight

—

There is no information about the cheapest roundtrip flight from Ontario to Denver

The fastest flight

2h 20m

Fastest flight from Ontario to Denver takes 2h 20m

Direct flights

Several times a week

There are direct flights on this route 2 days a week: Tu and Fr

Earliest flight

5:00 AM

Latest flight

6:30 PM

Direct flights count

69

Distance

1289km

Timezone difference

1h

The distance between Ontario and Denver is 1289km (799 miles). There are 69 direct flights from Ontario to Denver. The time difference between Ontario and Denver is 1h. Flights from Ontario begin at 5:00 AM. The latest flight from Ontario departs at 6:30 PM

Remember that on average the ideal time to book flights is 2 months before departure!

Airfare from Ontario to Denver by month

The minimum one-way ticket price from Ontario to Denver is $46 (August 2026), while the maximum is $140 (July 2026). On average, a ticket costs $107–$275.

August 2026

Lowest price

on average:

$46

July 2026

Highest price

on average:

$140

Avg Price

Price dynamics

On the Ontario — Denver route, prices first decline, hit a low, then start rising again. The middle of the period creates a price window — the best time to book.

Cheaper and more expensive periods

Prices fall from July 2026 to August 2026 (67%), then rise from August 2026 to December 2026 (+195%). The best period is August 2026–December 2026 ($90), the most expensive is July 2026–August 2026 ($93).

Best time to buy

The best time to buy is August 2026–December 2026, when prices are at their lowest. This can save you up to 3% compared to the expensive months (July 2026–August 2026).

Price predictability

Monthly price variation is 40.6%. On this route, your departure date noticeably affects the cost, and choosing wisely can lead to real savings.

Airlines operating on route

The route Ontario — Denver is served by several airlines: United Airlines, Southwest Airlines, and Frontier Airlines. This gives passengers more freedom in choosing flights. You can consider not only the price but also schedules, baggage policies, and onboard service. Our service compares all offers so you can find tickets from $34 and choose the most convenient option. Thanks to airline competition, you may also find promotional fares or special offers, helping you save even more. Plan your trip in advance and choose the best flights without overpaying.

United Airlines

starting at $161

Southwest Airlines

starting at $465

Frontier Airlines

starting at $34

Non-stop flights from Ontario to Denver

A non-stop flight is the most convenient and comfortable way to fly from Ontario to Denver, despite the fact that sometimes flights with transfers can cost significantly less.

Ontario — Denver

ONT — DEN

07/31/2026

Departure

Direct flight

UA1263

starting at $298

Ontario — Denver

ONT — DEN

07/28/2026

Departure

Direct flight

WN3146

starting at $465

Ontario — Denver

ONT — DEN

08/18/2026

Departure

Direct flight

F91500

starting at $107

Schedule of direct flights from Ontario to Denver

There are most likely no direct flights on the Ontario — Denver route

Ontario airports overview

Ontario International Airport

•

ONT

5km

Serves Ontario and the Inland Empire region of Southern California, offering domestic and select international flights; convenient for travelers to Los Angeles, San Bernardino and nearby business centers.

•

Denver airports overview

Centennial Airport

•

APA

1km

Denver International Airport

•

DEN

30km

•

Frequently asked questions (FAQ)

Answers to questions about the route that travelers are most interested in.

What is the cheapest price for flights from Ontario to Denver?

The cheapest flight ticket from Ontario to Denver according to data for the last 48 hours costs $34

When is the best time to buy air tickets on the route Ontario — Denver?

Often the best time to buy tickets from Ontario to Denver is 2 months before departure.

When is the cheapest time of year to fly from Ontario to Denver?

Based on statistics over the past years, the lowest prices for flights from Ontario to Denver can be found flying in these months: August, December, July.

How long does it take to fly from Ontario to Denver?

The fastest flights from Ontario to Denver start from 2 hours 20 minutes in the air.

Which airline can fly direct from Ontario to Denver?

The following airlines operate direct flights on the route Ontario — Denver: United Airlines, Southwest Airlines, Frontier Airlines

Special offers and sales on air tickets from Ontario to Denver

We keep tight track on airlines' pre-holidays sales and other special offers occurences all the time to let you save maximum amount of funds while traveling to your family or just going out on vacation.

We couldn't find any special offers for flights from Ontario to Denver

Alternative routes

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Cheapest one way flight

$34

Frontier Airlines

Direct flight

2h 25m

08/19/2026

The cheapest one-way flight from Ontario to Denver departs on 08/19/2026, is operated by Frontier Airlines and costs $34

Cheapest round trip flight

—

There is no information about the cheapest roundtrip flight from Ontario to Denver

The fastest flight