$49 Find Cheap Flights from Ontario to Colorado - 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 Ontario to Colorado departing on 10/26. 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

Save 20% or more on flights. Compare deals from all over the web.

Never overpay with our price tracking tools.

Filter searches by price, airline and more to find your best flights.

Flight Deals
Booking Insights
Flight Deals

Cheap Flights from Ontario to Colorado

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours
Denver
Denvernonstop$103
Aspen
Aspen1 stop$479
Vail
Vail1 stop$509
Grand Junction
Grand Junction1 stop$319
Durango
Durango1 stop$314
Montrose
Montrose1 stop$295
Denver
Denvernonstop$103
Aspen
Aspen1 stop$479
Vail
Vail1 stop$509
Grand Junction
Grand Junction1 stop$319
Durango
Durango1 stop$314
Montrose
Montrose1 stop$295

Book Cheap Ontario to Colorado Plane Tickets

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Ontario to Colorado that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Ontario to Colorado

Wed, Dec 9 - Wed, Dec 9
Frontier Logo
4:46 pm - 8:09 pm
ONT
-
DEN
2h 23mnonstop
Frontier Logo
10:55 pm - 12:20 am
DEN
-
ONT
2h 25mnonstop
$103Frontier
Thu, Aug 20 - Sat, Aug 22
Frontier Logo
6:00 am - 9:24 am
ONT
-
DEN
2h 24mnonstop
Frontier Logo
10:29 pm - 11:50 pm
DEN
-
ONT
2h 21mnonstop
$103Frontier
Thu, Oct 15 - Mon, Oct 19
Southwest Logo
5:40 am - 8:55 am
ONT
-
DEN
2h 15mnonstop
Southwest Logo
8:30 am - 9:55 am
DEN
-
ONT
2h 25mnonstop
$157Southwest
Sat, Dec 5 - Mon, Dec 7
Southwest Logo
11:20 am - 2:30 pm
ONT
-
DEN
2h 10mnonstop
Southwest Logo
1:20 pm - 2:40 pm
DEN
-
ONT
2h 20mnonstop
$157Southwest
Sat, Sep 19 - Tue, Sep 22
American Airlines Logo
6:15 am - 11:27 am
ONT
-
DEN
4h 12m
1 stop
American Airlines Logo
7:15 am - 12:06 pm
DEN
-
ONT
5h 51m
1 stop
$177American Airlines
Wed, Sep 16 - Sat, Sep 19
Delta Logo
9:52 am - 5:02 pm
ONT
-
DEN
6h 10m
1 stop
Delta Logo
10:45 am - 4:35 pm
DEN
-
ONT
6h 50m
1 stop
$197Delta
Mon, Nov 16 - Mon, Nov 23
United Airlines Logo
5:00 am - 8:17 am
ONT
-
DEN
2h 17mnonstop
United Airlines Logo
7:25 pm - 8:51 pm
DEN
-
ONT
2h 26mnonstop
$220United Airlines
Thu, Aug 20 - Sat, Aug 22
United Airlines Logo
5:00 am - 8:21 am
ONT
-
DEN
2h 21mnonstop
United Airlines Logo
11:30 am - 12:50 pm
DEN
-
ONT
2h 20mnonstop
$237United Airlines
Sat, Oct 17 - Wed, Oct 21
American Airlines Logo
1:05 pm - 6:50 pm
ONT
-
GJT
4h 45m
1 stop
American Airlines Logo
7:03 pm - 9:54 pm
GJT
-
ONT
3h 51m
1 stop
$319American Airlines
Tue, Sep 1 - Wed, Sep 9
Delta Logo
5:05 pm - 9:56 pm
ONT
-
GJT
3h 51m
1 stop
Delta Logo
7:41 am - 12:14 pm
GJT
-
ONT
5h 33m
1 stop
$319Delta
Booking Insights

KAYAK's insights & trends for Ontario to Colorado flights

Get data-powered insights and trends into flights from Ontario to Colorado to help you find the cheapest flights, the best time to fly and much more.

How much is a round-trip flight from Ontario to Colorado?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Ontario to Colorado departing in August.

Flight prices are below average for this route right now.

Flights to Colorado from Ontario usually cost between $122 and $256 in August.
The lowest price found in the past 5 days was $103 on Frontier (Aug 20-Aug 22).

What is the cheapest Ontario to Colorado flight route?

Data is based on round-trip flight searches on KAYAK over the past month.

The cheapest ticket to Colorado from Ontario found in the last 5 days was to Denver, at $164 round-trip. The most popular route is from Ontario (ONT) to Denver (DEN), and the cheapest round-trip airline ticket found on this route in the last 5 days was $164.

What is the cheapest time of day to fly to Colorado?

The average price for all round-trip flights from Ontario to Colorado depending on the time of departure, clicked by users on KAYAK in the last 2 weeks.

The cheapest time of day to fly to Colorado is generally at night, when round-trip flights cost $207 on average. Morning departures are around 48% more expensive than evening flights, on average. The most expensive time of day to fly to Colorado is generally in the afternoon, which is peak travel time and where the average cost of a ticket is $455.

Can I save money by flying with a layover from Ontario to Colorado?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

No, with an average price for the route of $313, prices are generally cheapest when you fly direct.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Ontario to Colorado, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Ontario to Colorado is February, when tickets cost $178 (return) on average. On the other hand, the most expensive months are June and July, when the average cost of round-trip tickets is $342 and $291 respectively.

What’s the cheapest day of the week to fly from Ontario to Colorado?

The average price of all round-trip flights from Ontario to Colorado clicked on KAYAK for each day over the last 12 months.

Your flight ticket price will generally be cheaper if you fly to Colorado on a Saturday and more expensive on a Sunday. On your return trip to Ontario, you should consider flying back on a Wednesday, and avoid Sundays for better deals.

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

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Ontario to Colorado, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Ontario to Colorado, you should book around 1 week before departure. For the absolute cheapest price, our data suggests you should book 9 weeks before departure.

Good to know

Low season

January

Cheapest flight

$49
Best time to beat the crowds with an average 15% drop in price.
Most popular time to fly and prices are also 18% lower on average.
Flight from Ontario to Denver

FAQs - booking Colorado flights

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

    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 Ontario to Colorado.

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

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight from Ontario to Colorado 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 Ontario to Colorado?

    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 Ontario to Colorado 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 Ontario to Colorado?

    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 Ontario to Colorado up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Top tips for finding cheap flights to Colorado

  • Looking for a cheap flight? 25% of our users found tickets from Ontario to the following destinations at these prices or less: Denver $185 one-way - $290 round-trip

Reviews of the top 5 airlines serving from Ontario to Colorado

 
See real verified KAYAK customer reviews for airlines flying from Ontario to Colorado. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Ontario to Colorado? 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.
8.0
SouthwestOverall score based on 4229 reviews
8.0Comfort
7.5Entertainment
7.0Food
8.6Crew
8.1Boarding
Airline reviews

Friendly crew kept coming by to make sure all was ok, provide additional refreshments, etc.

10.0 ExcellentTamara, Jul 2026
MCO - DEN
Read more Southwest reviews

Friendly crew kept coming by to make sure all was ok, provide additional refreshments, etc.

Flight was delayed by 2 hours, meaning that a flight to Dwnver which should have arrived at 11pm came into the airport at 1 am. Made for a very long day.

Crew was rude, flight was late, wifi didn't work, no food, basically nothing about this flight was good.

Flight was constantly delayed with significant changes in time, it was supposed to get to Colorado Springs at 8:30 PM but it got there after midnight.

Flight was delayed, full flight and I had to change gates. Southwest flights are always late later in the day.

Sacrament staff are always polite and helpful. Airport is easy to maneuver and boarding is straightforward.

The 700 model seating is too tight both seat size & leg room

Flights were full but SWA still managed to get everyone loaded and depart on time. No snack or beverage service on the first leg due to turbulance. Seats were clean but very little cushioning. Reasonable amount of leg room.

I liked receiving attention from aged and well experienced flight attendants. I disliked the non-gluten-free snack but I brought my own so I was OK.

Our two flights from GRR to MDW and MDW to OAK were both delayed due to weather. Be sure to build in a sufficient buffer in the transfer time to account for this type of problem. SW recommends connections as short as 40 min. Don't do this. We had to change concourses in MDW, a pretty long walk, to make our connection. Rule of thumb I use when traveling on flights with multiple legs is for connections of 80 min or more, unless there is no plane change, in which case it doesn't matter.

Smooth flight. Left on time, and got in 15 minutes early. Onboard video was great

Flight was canceled, and no effort was made to help with rebooking, no hotel vouchers, no car transportation and minimal food voucher and most places for food were closed by the time the voucher was given. Waited for 3 hours for bags. Simply the worst travel experience I have ever had

It was a great flight and the stewards and stewardess were all kind and accommodating!! The seats were comfortable and entertainment screen excellent!

My flight was 6 pm 6/6. Every hour they delayed it again - air condition issues then no pilot then the crew had worked too many hours and cancelled the flight at 11 pm. Sent customers to NJ a 45 minutes uber ride to a hotel. Had to be back by 5 am for a 7 am flight and again no pilot etc with another three hours of delays.

737-800 in first class was pretty dumpy. Seat had an uncomfortable angle, storage under the seat was blocked so even my very modest backpack didn't fit, power outlet was flaky. Weird tiny seat pockets that couldn't hold a gallon ziploc bag, emesis bag missing, etc. etc. No in-flight service due to turbulence. Crew was excellent, boarding was smooth despite a full flight.

Delta flight was on time, seats were comfortable, and crew was nice.

Airline lost my luggage and set me back a day worth of travel due to having to stay in Denver to wait on my luggage

The flight was overbooked and the staff at the gate started calling for volunteers to drop out and offering incentives. That delayed the flight

There was no wifi even after my husband paid for wifi it wasn’t working. The plane looked and felt old.

Update the cabin with tv screens or at least music sources.

Flight was late, the only reason I almost missed my flight was that my connection was also late.

Seat pitch is horrible especially on the 15 hour flight. Gate crew at SFO was Outstanding. The flight crew was also great.

Booked through Kayak Business, had a seat in middle and towards back due to booking rate, not comfortable.

I had a cancelled flight because of technical issues going to my destination, and a delayed flight coming home. All told it wasn’t a total bust.

Seats are uncomfortable. This has been a trend in the industry for decades. Trying to fit more seats on each plane to increase profits at the expense of the passenger.

Women boarding passengers at the gate was absolutely rude and disrespectful of passengers. The flight attendant was absolutely delightful! Smiling and connected with the passengers. So happy. The seats are cramped and uncomfortable but I guess that’s just the way it is Communication regarding flight was excellent

I understand stuff happens, but plane failures are likely due to lack of maintenance. Additionally, air conditioning wasn't working, no snack/drink service, no WiFi. Fortunately, the crew was communicative and light-hearted. United grabbed another plane and we were able to get to our destination.

I was supposed to be on business class at first class from Denver back to Miami due to weather changes. I missed my connection and it’s put on a flight to Fort Lauderdale. Instead of honoring my business class/1st class ticket, they put me in coach, but there were two first class seats open. I think it’s absolutely disgusting that I paid for first class $1300 ticket and they put me in economy and they had to open seats available and I have still not been refunded the difference. I ended up having to eat a snack box instead of the meal I was supposed to get and did not get home till 2 AM so I think that’s a little pathetic that I had to live off crackers for dinner And my poor dog ate some cheese and salami. Oh yes, apparently when they switched me to the new flight they forgot to mention I had a service dog

It was fine. The flight attendant appeared to be in a bad mood but everything was fine.

I am not an electronic savy. I don't know how to maneuver the APPS for services. Why can't I just buy food without the apps.

American was the airline that Starlux contracted for this trip. I arrived in time to make the connecting flight on American, and then the baggage-handler debacle happened. For some reason, the first class and premium economy passengers' luggage was unloaded first. Never seen this happen before. They had handlers removing the bags from the carousel for those passengers. Meanwhile, all of the economy passengers were waiting for their bags, including me. And there were a lot of bags because it was an international flight packed full. While waiting for 45 minutes, my bag didn't show. Meanwhile, an American representative showed up asking if anyone has a connecting flight to Phoenix. Of course I spoke up, and they proceeded to try to find my bag because I had to take a bus to the actual terminal to catch my flight. Which I was not informed of before I arrived. After another 15 minutes of searching, my bag was finally found with the first-class passengers' bags because they had pulled it by mistake. So I rushed to the terminal with the American representative to catch my flight, and they informed me that I missed it and could not get another flight until the next day. Of course, after being on an international flight for 18 hours, I was in no mood to hear this. Now, to be fair, there were a few American employees who tried to help me. After hearing about the missed flight, they got a supervisor to talk to. I expressed my situation to the supervisor, and she was not helpful until I asked for compensation. She agreed to get me a hotel room for the night. So I agreed, and she disappeared into her office, and I waited. And waited. And waited. And waited. While waiting, I was asked by three different employees who knew of my situation if I had been helped. I told them I was waiting for the supervisor to get the hotel room, and they said they would check. Finally, after waiting for 75 minutes, one of the employees who had asked me if I had been helped arrived with my hotel room and arranged a ride to the hotel for me. Never saw the supervisor again. It was now 8 o'clock; I arrived at 5:45! My rebooked fight was scheduled for 6:11 this morning and I have now been informed it has been delayed until 10:00. So am I happy with American? NO I'M NOT!! ;

Ontario airport boarding was very easy to park and access, is clean and TSA took 10 minutes total. Check-in was a breeze and cruise was very nice.

Everything was delayed and the staff sent me to the wrong gate, causing me to miss one of my flights. I arrived at my destination 6 hours later than I was supposed to.

Good flight, seated and had a water within 5 minutes. Crew was hospitable.

The flight was fine. It's the satellite terminal that supports American eagle flights is what sucks. There is only one food option and everything there is way overpriced. I mean I know it's airport pricing, but it's even crazier than that. I bought a sandwich in a plastic container for $18.

The flight was on time and arrived early. The crew were friendly and helpful.

The chair cushions may need an upgrade. I have been noticing they are so worn out, thin so you’d sit in a dip 😄. Other than that, all was an enjoyable trip. Thanks AA!

VERY disappointed at the agent checking in my luggage. I know that the weight limit is 23 kg, a little over 50 pounds (50.71 pounds). Yet the agent kept repeating "50 pounds". So I said, the limit is 23 kg, and she had the audacity to say 'no, it is 22 kg!" Imagine my surprise. Was she ignorant or was she poorly trained? Not sure. The boarding process was pretty good. The speakers were loud enough so I still could hear them despite inconsiderate passengers continuing to speak while the announcements were going on. During the flight, the teenage girl sitting behind me kept pressing her feet to the back of my chair. I turned around several times, yet she did not get the hint. I did not make a fuss since I sense I had a bad streak that night with AA, so I just did the best I can to lean forward and not let that bother me.

WiFi was down so no entertainment and I could not work either. The flight was Very turbulent at the end (the last 20 min felt like an eternity) I appreciated the pilot for getting us there safely. The flight attending in first class was kind and attentive to everyone.

It was wonderful upgrading to first. Plane was so cold thou. Crew was great. Wish there was a food option in first for such a long flight. Doesnt matter the time of day. Chintzy.

It was awful ....my first time flying on it and I will NEVER fly it again ....everything about it was terrible .....most especially the flight attendants

The takeoff was the smoothest I've ever experienced on any airline and this is the first time I've flown on frontier so this was an extremely pleasant surprise!

A lady asked to stop the flight after the tunnel pulled away and we began to depart a flight that was already hours late. The attendance respectfully stopped the the plane and had the tunnel return. After the tunnel returned the passenger claimed to have changed her mind . The tunnel was then put in reverse and the passenger remained on the plane .. They should have sent the sick passenger off the plane like initially replaced. They existed a couple off the plane prior to that situation.. So.. all and all.. it was a long and flight.. .

We understand and comply with Frontier’s bag sizes. We’ve had some problems in past while having to await other passengers who do not understand the baggage restrictions or have not prepaid and that is usually our biggest concern (others delaying us) with flying Frontier. Flying OUT of ONT, however, has always been a great experience. I’ve also noted even on delayed Frontier flights very knowledgeable pilots who manage expectations well.

Long lines, rude staff, everything that's offered you have to pay for.

The last time I flew Frontier was in the 1960s when it was a “real” airline. We flew this time because of the price & schedule. As the saying goes, you get what you pay for.

I appreciated the upgrade to free cary-on bag and seat selection at no charge

Flight was delayed on the runway for 40 minutes the crew did not even offer even water to passengers to compensate for the flight delayed. The flight was delayed due to aircraft mechanical issues. Worst customer service ever

This isna terribly run airlines. If you're one minute late, they will deny your ticket. Don't waste your time or money

Flight was delayed for more than 3 hours, crew at ONT airport was rude, and when we got to DFW the airplane had an issue landing, we had to be taxied to the terminal, and the luggage was hold until the next day.

Everything you need to know for your flight from Ontario to Colorado

Information on your arrival and departure airports