$139 Find Cheap Flights from Colorado to Ontario - Compare and Save

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Colorado to Ontario departing on 9/27. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

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Good to know

Low seasonFebruary
Cheapest flight$139
Best time to beat the crowds with an average 12% drop in price.
Most popular time to fly and prices are also 2% lower on average.
Flight from Denver to Toronto Pearson Airport

FAQs for booking flights from Colorado to Ontario

  • How does KAYAK find such low prices on flights from Colorado to Ontario?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Colorado to Ontario.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Colorado to Ontario?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Colorado to Ontario is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Colorado to Ontario?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly from Colorado to Ontario with an airline and back with another airline.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Colorado to Ontario?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying from Colorado to Ontario up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

  • Which airlines fly most frequently to Ontario?

    Air Canada connects Colorado to Ontario with 30 flights per week. United Airlines also offers 30 flights per week, while Austrian Airlines follows with 7 flights per week.

  • How many airports are there in Ontario?

    There are 24 airports in Ontario. The busiest airport is Toronto Pearson Airport (YYZ), with 78% of all flights arriving there.

  • Which is the cheapest airport to fly into in Ontario?

    Prices will differ depending on the departure airport, but generally, the cheapest airport to fly to in Ontario is Toronto Pearson Intl Airport (YYZ), with an average flight price of $395.

  • What is the cheapest day to fly to Ontario?

    Based on KAYAK data, the cheapest day to fly to Ontario is Thursday where round-trip tickets can be as cheap as $693. On the other hand, the most expensive day to fly is Sunday, where round-trip prices are $805 on average.

  • What is the cheapest time of day to fly to Ontario?

    The cheapest time of day to fly to Ontario is generally in the afternoon, when round-trip flights cost $702 on average. Morning departures are around 5% cheaper than evening flights, on average. The most expensive time of day to fly to Ontario is generally in the evening, which is peak travel time and where the average cost of a ticket is $790.

  • What is the cheapest flight to Ontario?

    The cheapest ticket to Ontario from Colorado found in the last 5 days was to Toronto Pearson Intl Airport, at $429 round-trip. The most popular route is Denver (DEN) to Toronto Pearson Intl Airport (YYZ) and the cheapest round-trip airline ticket found on this route in the last 5 days was $429.

  • What is the cheapest month to fly from Colorado to Ontario?

    The cheapest month for flights from Colorado to Ontario is September, when tickets cost $95 (return) on average. On the other hand, the most expensive months are April and January, when the average cost of round-trip tickets is $252 and $198 respectively.

  • How far in advance should I book a flight from Colorado to Ontario?

    To get a below average price on the flight from Colorado to Ontario, you should book around 4 weeks before departure, which saves you about 55% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 7 weeks before departure.

  • How many cities have direct flights to Ontario?

    From Colorado, there are direct flights to Ontario from 1 city. This city is Denver and there are 71 direct flights each week.

  • How many direct flights to Ontario are there each day?

    There are around 10 direct flights from within Colorado to Ontario every day. Most flights (59%) depart in the morning.

  • How many direct flights to Ontario are there each week?

    Each week there are around 69 direct flights from within Colorado to Ontario. The most common day for departures is Saturday, with 16% of flights taking off on this day.

  • How long is the flight to Ontario?

    An average nonstop flight from Colorado to Ontario takes 8h 31m, covering a distance of 1422 miles. The shortest route is Denver (DEN) to Toronto Pearson Intl Airport (YYZ) with an average flight time of 3h 12m.

  • How many long-haul flights are there to Ontario each week?

    There are not any long-haul (6-12 hour flight duration) or medium-haul (3-6 hour flight duration) flights to Ontario. Instead, there are 69 short-haul flights (up to 3 hour flight duration), with the most arriving from Denver.

  • What are the most popular destinations in Ontario?

    Based on KAYAK flight searches, the most popular destination is Toronto (96% of total searches to Ontario). The next most popular destinations are Ottawa (3%) and London (1%). Searches for flights to Thunder Bay (0%) and to Kingston (0%) are also popular.

Reviews of the top 3 airlines serving from Colorado to Ontario

 
Need help choosing which airline to fly with from Colorado to Ontario? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
7.4
United AirlinesOverall score based on 9895 reviews
7.3Comfort
7.7Boarding
8.1Crew
6.6Food
7.1Entertainment
Airline reviews

Entertainment kept turning itself off. Gave up on watching a movie.

8.0 ExcellentLeslie, Feb 2026
SFO - YYZ
Read more United Airlines reviews

Entertainment kept turning itself off. Gave up on watching a movie.

Wifi took a while to kick in and we had a maintenance issue that took over 40 mins at the gate in Washington before pulling back

Not United Airlines' fault. It's ORL airport's fault.

United overall experience is great these days. Airport experience was very organized. Staff on flight were great. App and information as good as it gets.

Very nice flight love the small aircraft. We had a wonderful flight attendant. Nice to see someone that really enjoys her job. Don't have her name but had a southern accent.

Seats in waiting area and on plane hard as rock. Fast internet on the flight was great! Crew was kind.

Not the fault of United—weather, reroute around weather, time sitting on tarmac, arrived couple hours late, too late for train into city necessitating a much pricier cab but weather…can’t be helped.

I had no checked baggage but was required to hand over carry on baggage at the door of the plane. There was a lot of overboard space in the plane and I was one of the last ones. I ran to get my carry on but it was gone. I was given back at the plane door in Toronto, so the wait was not as long as it would have been at the carousel.

the delay for 3 hours was understandable due to weather conditions but the flight should’ve provided some on flight compensations or at least provide more food.

I do prefer to fly United and have always had excellent service, except for bad weather. Flights are on time and staff is alway curtious and helpful

Westjet was late and we missed our connecting flight with Cathay. Had to wait 8 hours. Westjet only allows 1 checked in baggage for international flights- it’s always been 2. Canada allows only 1 sandwhich bag size full off small liquids. Everything else will be tossed. Awful trip. Will never fly west jet or go to Toronto to connect flights!

Everything was good except for flight delay, but it was because of the snow storm in the arrival airport.

West Jet flight was cancelled and I was not notified. I found out when I tried to check in on-line. Spent 4 hours on the phone with West Jet and Just Fly trying to figure what happened.

Flight was delayed 3 times. Then cancelled due to pilot being timed out. They refused hotel vouchers. Gate attendants were very rude and could not help you at all.

Flight was on time. Online check in capabilities made things quick and easy. Zone boarding was enforced, which I appreciate. Everyone was not lining up ahead of their zone being called. Crew was professional and friendly.

The big lady was sitting right next to me and the button to recline my seat was blocked by her huge arm. No power outlet for chargers. No inflight Wi-Fi movies

Trip was uneventful which is good. Boarding took a long time due to many disabled/elderly requiring assistance which again is fine. Landing and take off were excellent. Food and entertainment were as expected, bring your own if you have preferences otherwise you get what you get.

Okay but not like typical first or business class. On domestic airlines

I liked the kindness of the check in counter crew, the flexibility with changing seats and the comfort. Better free drink selection would have been good but it wasn't a long flight.

Flight was on time… crew normal experience… captain was informative. Boarding at the gate had a bit chaotic ,but overall, it was an enjoyable full flight and I thank you as it was my first time flying Westjet and I will do it again. Regards

We had a very long delay. First the inbound flight took a while, then maintenance, they “fixed it” to then do boarding and leave the gate, and waste a lot of time to have to go back to the gate and eventually deplane. Had to wait for a new aircraft, wait for a gate, and do the whole thing again. Instead of leaving at 9:50am we left until past 1. I could’ve not woken up at 5am, or spend some more time with my family if they gave more grace period of time between flights to give some time in case of any issues. But they have to make all and every dollar possible

Most expensive flight… and they are trying to pinch more and more money out of you. Baggage, snacks, pillows, headphones… — so many airlines do far better than this… surely a national airline can do better?

Air Canada should allow basic economy passengers to upgrade if they wish to do so.

My second flight ended up being through United and it was fine. Again, just frustrating that it was so late.

I had written all my complaints on my trip from Grand Junction to Denver so I will repeat it here! I was absolutely appalled that I had to pay for a regular seat that I choose 24 hrs before boarding! Also I checked my large bag which I had to pay for as well, and by the time I boarded all the room in the bins were gone so also had to check that one. I noticed people pulling out oversized suitcases, bigger than the measurements stated for carry on, and also large pack packs stuffed full! So these people were taking up 2 or 3 spaces that the rest of us should have been able to use but couldn’t! NoTV on the flight! Thankfully I had downloaded the United Airlines app and was able to watch movies on my phone. Don’t remember the last time I flew in a plane with no movie screens!

My flying experience with Air Canada was good but the wheelchair situation wasn't good at all and if would be good to make sure that they have the appropriate services available for your traveling passengers.

Air Canada flights offer excellent service. This flight from DEN to YYZ in an Airbus A220-300 was so sooth it was almost like spending a couple of hours reading a good book, except for the cabin crew who provide friendly, thoughtful service throughout the flight. Kudos to AC pilots, cabin crew and management. I’ve now added Airbus 220.300 to my preferred list if planes to fly in.

Lots of delay! Cheotic and disorganized! Aircraft had technical problem and was stopped and returbed to the gate while taking off! . United States is sinking under Joe Biden!

Ops was very poor. 2 of 2 legs were both late. Air Canada changed our seats 3x and my friend and I never did get to sit together. Flight attendant opened the lavatory on me and was not professional about it. Food was blah. The worst part is that the flight was so late from Toronto that we missed our connection in Athens. We lost out on other airline tickets and nobody even said sorry or tried to help. Our return flight was cancelled and my friend and I are rebooked on completely different flights next week.

Legroom was not good and can be improved and food needs upgrade.

Everything you need to know for your flight to Ontario

Cabin class types available on flights to Colorado

Cabin classes available on flights to Colorado. Prices are the lowest found on KAYAK over the last 7 days. Price and availability is not guaranteed.