$86 Find Cheap Flights from Ontario to Colorado

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 6/8. 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

KAYAK searches hundreds of travel sites at once for deals on flights to Colorado

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to Colorado, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Ontario to Colorado, as well as popular online travel agencies
Travelers love KAYAK
41,299,237 searches in the past 7 days on KAYAK

Save 24% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Bundle and saveSave money when you bundle your flight + hotel.

Filter your dealsChoose cabin class, free Wi-Fi and more.

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$102
Aspen
Aspen1 stop$389
Vail
Vail1 stop$329
Grand Junction
Grand Junction1 stop$271
Durango
Durango1 stop$314
Montrose
Montrose1 stop$338
Denver
Denvernonstop$102
Aspen
Aspen1 stop$389
Vail
Vail1 stop$329
Grand Junction
Grand Junction1 stop$271
Durango
Durango1 stop$314
Montrose
Montrose1 stop$338

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

Thu, May 14 - Tue, May 19
Frontier Logo
10:50 am - 2:12 pm
ONT
-
DEN
2h 22mnonstop
Frontier Logo
10:29 pm - 11:49 pm
DEN
-
ONT
2h 20mnonstop
$102Frontier
Sat, May 23 - Tue, May 26
Frontier Logo
6:00 am - 9:22 am
ONT
-
DEN
2h 22mnonstop
Frontier Logo
8:41 am - 10:05 am
DEN
-
ONT
2h 24mnonstop
$106Frontier
Mon, Jun 1 - Wed, Jun 3
Delta Logo
6:00 am - 11:15 am
ONT
-
COS
4h 15m
1 stop
Delta Logo
8:15 am - 12:19 pm
COS
-
ONT
5h 04m
1 stop
$197Delta
Sat, May 16 - Tue, May 19
Southwest Logo
5:40 am - 12:35 pm
ONT
-
COS
5h 55m
1 stop
Southwest Logo
6:00 am - 9:50 am
COS
-
ONT
4h 50m
1 stop
$258Southwest
Tue, Jun 30 - Tue, Jul 7
Southwest Logo
4:10 pm - 11:45 pm
ONT
-
COS
6h 35m
1 stop
Southwest Logo
7:55 pm - 11:00 pm
COS
-
ONT
4h 05m
1 stop
$259Southwest
Mon, Jun 1 - Wed, Jun 3
Delta Logo
6:00 am - 11:15 am
ONT
-
COS
4h 15m
1 stop
Delta Logo
11:55 am - 10:32 pm
COS
-
ONT
11h 37m
2 stops
$263Delta
Sat, May 9 - Mon, May 11
American Airlines Logo
2:08 pm - 9:23 pm
ONT
-
DRO
6h 15m
1 stop
American Airlines Logo
6:38 pm - 9:59 pm
DRO
-
ONT
4h 21m
1 stop
$314American Airlines
Sat, May 9 - Mon, May 11
American Airlines Logo
9:33 am - 9:23 pm
ONT
-
DRO
10h 50m
2 stops
American Airlines Logo
6:38 pm - 9:59 pm
DRO
-
ONT
4h 21m
1 stop
$320American Airlines
Wed, May 13 - Sun, May 17
United Airlines Logo
1:40 pm - 9:06 pm
ONT
-
DRO
6h 26m
1 stop
United Airlines Logo
7:00 am - 12:38 pm
DRO
-
ONT
6h 38m
1 stop
$323United Airlines
Sat, Sep 19 - Tue, Sep 22
United Airlines Logo
1:18 pm - 8:54 pm
ONT
-
DRO
6h 36m
1 stop
United Airlines Logo
5:20 am - 12:12 pm
DRO
-
ONT
7h 52m
2 stops
$324United Airlines
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 May.

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 72 hours was to Denver, at $115 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 72 hours was $115.

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 57% 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 $431.

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 $258, 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 January, when tickets cost $39 (return) on average. On the other hand, the most expensive months are November and August, when the average cost of round-trip tickets is $85 and $59 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 Friday and more expensive on a Monday. On your return trip to Ontario, you should consider flying back on a Saturday, 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 8 weeks before departure.

Good to know

Low seasonJanuary
Cheapest flight$86
Best time to beat the crowds with an average 10% drop in price.
Most popular time to fly and prices are also 5% 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 $134 one-way - $232 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 4314 reviews
8.6Crew
8.1Boarding
7.0Food
7.5Entertainment
8.0Comfort
Airline reviews

The entire experience from boarding to landing was amazing! The crew were very friendly. Will definitely be back.

10.0 Excellentlarry, Apr 2026
LGB - PHX
Read more Southwest reviews

The entire experience from boarding to landing was amazing! The crew were very friendly. Will definitely be back.

Delayed flight, lack of information, boarding process is a mess as is the carryon luggage causing issues when leaving the plane….just a poor experience.

Comfortable. Easy. No problems. Just wish they had gf options for snacks.

The crew was very kind and made going to Hawaii relaxing and fun to look forward to! Thank you Southwest for a pleasant flight!

We waited in the airplane for over 45 min for a southwest employee to make the flight. This cause over half the plane to miss their connecting flight in Denver. When we confronted the desk upon arrival, they told us the only flight they had was the next day leaving at 8:50 pm!!! Or they offered to get us to Burbank or LA, but after that we were on our own to get back to Santa Barbara. I paid for a flight from sba to bna bna to sba. My re entry into mom mode has been 💯 rough because of southwest mistake with my flight. And now I’m leaving to Reno tomorrow for a vballl tournament and just discovered that my leg in Vegas has me and my 3 kids on a stand by flight even though I had booked these ticket last year November!! Do better southwest!

Terrible. Even though there’s assigned seating now, they are still the slowest boarding airline of anyone.

It was good from LAX to Phoenix, But the connection in Phoenix to Tulsa was not that great. The staff on both flights were great. The choice of free entertainment was ok nothing to brag about. The 45 min delay because of some electrical issue wasn't great from Phoenix to Tulsa. We sat there with hardly any air, The seat I had was between windows so the side of the plane pushed in on you. My being a bigger man it then made the seating area uncomfortable. The seats on the plane had no power to connect to recharge your phone or anything. I would recommend that they should look into a slot or clamp to hold your phone to enjoy while watching the entertainment choices hands-free. Also make it possible to raise the inner seat by the window be able to raise the arm rest up to make more room for larger people to set more comfortably. I would also say other then that stop price gouging the airfare or nickel and diming everything. Not fair for people having to fly for emergencies and be paying for higher prices due to the season or holidays. Your making your money either way and the cost of flying is still going to be the same regardless if there's 100 people or 200 people.

Southwest was greaat! The most expensive but the least upsetting for those we were flying to see.

Boarding was easy. The seats are small and fairly uncomfortable

The problem with the seat assignments is that there were a lot of rows in the front that were empty but my row at the back was full. Just not so pleasant.

While they turned off most cabin lights to allow people to sleep, I was bothered by how bright the side lights still were. It was still quite bright for me in a window seat, when I wish I could have slept!

Generally on time departures and arrivals, clean planes, sky miles membership provides great benefits (complimentary upgrades, etc).

N Everything was perfect from boarding to assistance to baggage in Tampa

Loved the crew! Sucks that we went from 1 hour and 8 minute layover to a 3 hour layover. But weather sucks like that.

Fast, lovely scenery, great info on the Delta flight screen about landmarks we were flying over. Great landing!

Long flight but comfortable and not freezing as I have experienced on Hawaiian flights to the islands. They gave us blankets just in case. Nice touch.

I took seat 15A in anticipation of window seat, there is no window.

Flight late, the waited for a long time for “personal” to arrive at gate to dock the plane in Rochester. So annoying. This flight was expected, why aren’t personel available for the jet bridge?

My recent experience was excellent on Delta! I flew with Delta Comfort and I was really comfortable in my seat. I enjoyed the in-flight service. The flight attendants were so friendly and hospitable. I love the snack on the flight as well. This was my first time flying on Delta and I will definitely consider flying with them again.

My flight was canceled on Sunday. Rebooking took three hours. Had to pay for accommodations another night. New flight was delayed for 5 hours, all that was sent was a 12 dollar food voucher, which doesn’t tell you how to use it. Then when we landed we had to sit on the plane for an hour before we could get off.

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

They told us yesterday APR21st that they were cleaning the plane and we got delayed. After that they said they didn't had any crew for the flight so they cancelled the flight till next day.

The flight crew on this leg of my trip was very friendly and pleasant. Every one of them was humorous, as well as helpful and accommodating. This group was BY FAR the best crew I’ve flown with. They deserve kudos.

The entertainment options on the seat back video boards were nice.

The boarding process was straightforward. One pertinent observation regarding all boarding procedures is that if an individual requires assistance or possesses a special status and is part of preboarding, it is advisable to limit the number of passengers who can preboard with them, rather than the entire, sometimes large, companion groups. The seats are uncomfortable, and the entertainment options are significantly inferior compared to other airlines. During the snack service, I requested an additional bag of snacks, but my request was denied. Initially, the flight attendant agreed to my request.becoming a strange accurate moment. The flight duration was four hours.

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.

During landing. 2 crew members passed 3 times by my lane and didn't notice that people in front of us had their site to the furthermore reclined... That was uncomfortable and could have been dangerous.

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.

It’s always a great time flying with united airlines.

We got delayed three hours and nobody thought to have the bathroom fixed while we were sitting waiting to board? took a full hour to have maintenance come and check it off. Had to shut the bathroom down twice so that the pilots could go to the bathroom. Everyone missed their connections.

Left early arrived early..right amount of talking from pilots..of course had to love the biscuit and water!

Boarding gate at LAX was too crowded—two gates next to one another

On time departure and early arrival. Flight attendant 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.

The SFO Lounge crew were amazing. The bartender Faris was great. Thanks!

Was not able to do a online check-in because the American Airlines system doesn't store our visa or other passport information, allowing us to have a trouble-free check-in. We were forced to have to check-in at the counter which Changes are upgrade status given that we were not able to check in much earlier.

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

We left at 1030 am pacific from LA and supposed to land at 7 pm Eastern in NY. They made a detour, stopped in Philadelphia and didn’t land till 1130 PM Eastern!!! Worst flight experience with no pilot communication with no explanation as to what was going on. Everyone was very frustrated to say the least.

Flight boarded from Gate 159B, the farthest gate in the LAX Bradley Terminal. While the flight operated on time, the first class cabin attendant made no recognition of my being an Advantage Executive Platinum member.

The flight itself was excellent but the gate attendant made me check my carryon since she said it was an inch too big. I’ve had no problems with this carryon on recent flights on Qantas, Delta, Austrian, Southwest Airlines even though the overhead bins are the same size. there were other carryons in the bins that also looked larger than mine and there was room left in the bins for more. When I picked up my carryon from baggage claim one of the wheels had broken off.

It was an early flight and most people napped/slept and the crew let us which was nice.

More inflight connection. And leg space is horrible. And the paying for baggage I'd ridiculous!!!

It was costly and difficult to check in. $85 to take a small suitcase with me, carry on or checked and $75 on the return trip, Plus $25 if I didn't check my self in check in $25, because I couldn't do it on the kiosk. Small very uncomfortable seats, waited on the runway for near an hour each way. It was my worst flight to date.

Due to weather, my flight was delayed, further delayed, then canceled. I eventually got through to a support person who helped me find a different route out of MSP, but to get to DIA, they didn't want to, but eventually did help with the connection ticket purchase. But even this replacement flight was delayed time and time again, and I would have missed my connecting flights and I didn't want to get stuck in a layover city, so after 12 hours at the airport with two young boys who were very tired, we just cancelled our plans and spent the week at home, instead of Nana's.

I knew going into this that Frontier, being a low cost carrier, would be pretty bare bones and charge for most extras but this was made up for by the fact that the airplane was a reasonably new Airbus, every employee was great and best of all, Everett Washington is an amazing airport - thanks Frontier for flying there!!!

Seats were new and comfortable. Staff was fine. Missed my connection due to weather -which wasn’t their fault- but got no help at all. Gate staff sent me to customer service, which was and stayed unstaffed. Sign with QR code directed me to call or chat. Chat was useless. Call was returned after an hour. No itinerary offered by Frontier could get me home in less than 30 hours. Rebooked with another airline and got a partial refund that came to about 10 percent of what I paid to get home.

The experience was good. No frills but I got there safe and sound and on time.

As every law enforcement agency I could imagine surrounded the plane and we didn’t disembark for 2 hours and then had to stick around for another hour to go get our personal belongings after leaving them behind and being bused away from the plane, it was scary and inconvenient. We were given no information as to why this was happening. Lack of communication with passengers was disappointing.

Frontier Airlines was AWFUL. I was an hour early for my flight and the lady refused to check me in. I had to purchase a whole new ticket with a different airline.

Late, terrible communication, horrible planning of passenger seating until the literal last minute. One of the worst flying experiences of my life. Y'all suck

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

Information on your arrival and departure airports