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Find cheap flights from Ontario to Colorado from $38

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 6/17. 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
0 bags
seg 7/8
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Best Colorado Flight Deals

Cheapest round-trip prices found by our users on KAYAK in the last 72 hours

Denver
Denvernonstop$48
Aspen
Aspen1 stop$394
Grand Junction
Grand Junction1 stop$339
Vail
Vail1 stop$472
Durango
Durango1 stop$452
Montrose
Montrose1 stop$300

Good to know

Low season

January

High season

July

Cheapest flight

$38
Best time to beat the crowds with an average 7% drop in price.
Most popular time to fly with an average 11% increase in price.
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 to Colorado from 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 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 to Colorado with an airline and back to Ontario 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 to Colorado from Ontario up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

See more FAQs

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 $93 one-way - $162 round-trip
  • Morning departure is around 8% more expensive than an evening flight, on average*.
*Average of the lowest prices shown in KAYAK’s search results for departures within the next 30 days

Top 5 airlines serving from Ontario to Colorado

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.
8.2
China AirlinesOverall score based on 884 reviews
8.0Comfort
8.6Crew
7.8Food
8.1Entertainment
8.3Boarding
Airline reviews

The flight who provided services on my row had some not-nice attitude and not smiling at all.

10.0 ExcellentAnonymous, Jun 2024TPE - LAX
Read more about China Airlines reviews

The flight who provided services on my row had some not-nice attitude and not smiling at all.

Comfort was left wanting due to such a long flight, made the wife and I wish we could upgrade the seats to Business class or First Class, but did not have that option. Food was good but had very limited options and I have a dietary restriction which was difficult for the staff to accommodate since everything provided came with cheese on it. (Cheese could potentially kill me) Did not have an option to inform the staff until we were already in the air about the restriction and was not provided another option before flight departed.

The plane was uncomfortable. I paid extra for more legroom but the seat was still uncomfortable. Other seats on the same exact row didn’t have to pay extra but still have extra legroom. I didn’t understand why I needed to pay $170 for. It was Iike China airline just wants to make money off their passengers. It was unfair.

3 of the 4 flights had delays despite the weather being fine, but still managed to make all connections

Ask flight attendant for water during flight and she was a little rude get the water.

Baggage made it successfully to destination despite short layover. Appreciate that.

Staff were good and nice. There should me 3 meals instead of only 2 and snacks.

Excellent staff made the boarding process fast and easy. Friendly crews on both flights from Saigon to Taipei and Taipei to Los Angeles. Will fly China Airlines again.

For a long-haul flight, the crew did a very good job of keeping the lavatories clean and the aisles clear.

The check-in crew at SF did not put on breakable glass stickers on check-in baggages which caused my antique whisky bottle to break during transportation.

There was plenty of overhead room but half of the passengers were told they had to check their carryon bags. My partner and I checked in as early as possible and our seats were split across the aisle.

Flew first class so everything was great. But maybe because the flights were red eye, no meals were served, just chips. I flew Alaska Air 1st class at 9PM (2 hour flight) and they served beef short rib sliders!

I'm a larger, athletic guy (6'2", 260lbs powerlifter) and I found the seats incredibly uncomfortable with minimal leg room, especially in a window seat. Now, I full understand that being smaller may change my view but even if I was 80lbs less, my legs would be the same size and I was sandwiched between my seat and the seat in front of me.

There was a loud squeaky sound the whole time we were flying.

I didn’t not like that I could not select my seat and ended up with the worse seat.

The landing was bad and the hostess came two times and i was sleeping but when she served the person that nexts to me I woke up and she didn’t even asked me if I need any drink or snacks two times!!!!

The helpful attitude of the staff, and being a wheelchair passenger everyone was helpful and understanding. The trip was made comfortable by the upgraded seat which was given without my request, that was a great surprise. Thank you Delta.

Plane was late because of a mechanical malfunction and the food listed as available was not. Flight attendants seem over worked and under paid. They just done seem happy. And that can be seen in their faces.

Waited 3 hours on a plane to de-ice due to manpower issues. Waited another hour and a half once we landed because of a gate issue. Missed my connections. Created. A total of 13 hours of delay.

Great, on time departure, friendly and accommodating crew, great leg room, Smith flight

Horrible, the flights kept delaying, so it is obvious that we won't be able to make it to the next connection. No easier/real agent on site to help you figure this out. UA agent on other counters refuse to assist you and direct us to use the QR code/call customer service. So inefficient and poor. While technology seems convenient, but it's not the best interest/experience for customers need help while there is active issue need assistance.

Not worth the price of premium class ticket paid, felt more like steerage.

The Wi-Fi was unavailable on this flight for some reason.

This was a Lufthansa flight, not United. The CSA at the counter, Ashley, was not only incompetent, but quite rude. Me and two other PAX waited over 7 minutes standing in front of her and another CSA and they ignored us. We joked that we must have accidently taken invisibility pills. She could have at least said "I'll be with you in a moment, I'm currently....". I could go on about how rude she and the other CSAs were (whispering, not communicating with me, blaming the situation on others, etc.). She would not work for me. Then, she gave me literally the worst seat on the plane. the worst. My seat kept getting bumped (rammed twice by the crew with their carts and about every 5 minutes by someone using the bathroom), listening to the bathroom all night, crowded seat, etc.

We ended up with seats in the very back. So they did not recline. Have no idea why, we reserved and checked in very early. The isles were very narrow and the seats had very little leg room. But they did give us water, and a snack.

I paid $380 for my one-way ticket from California to Minnesota. The fair did not include online check-in. I received instructions from their app to check in at a kiosk. At the kiosk, the boarding pass would not print until an actual person came to verify that I had a personal item and not a carry-on item, On the plane, the person next to me was drunk and allowed to continue to order alcohol. United is garbage I’d rather fly spirit.

The plane was dirty and the in seat air wasn't blowing as planes usually do.

Positive: Entertainment via phone on the short was great and my first time. Good food and wine and head phones for free. Negative: Seat hardly reclined on the long flight. Breakfast was an egg with a bun. No egg choices and rather have something sweet like bun/jam and Youghurt.

They did get us booked on a later flight, but it made us miss our connecting flight. So, we had to stay and another state overnight with no luggage or clothes. Because they kept our luggage at airport for next flight on the next day.

Flight was on time. Staff were friendly. I paid for Economy Plus but was required to check my standard carry-on luggage due to lack of space on the aircraft. This cost me 30 minutes, unexpectedly, in waiting at the baggage claim. This experience did not meet my expectations.

The flight was delayed several times without explanation. The seats were terribly uncomfortable and wifi isn’t included. All these make for a less than ideal flight.

Internet service was erratic. Crew service was poor and slow. My luggage on this non-stop flight was lost and not recovered

Flight was 1/2 hour delayed leaving Phoenix. Otherwise it was an average flight. Flight crew on this trip was very nice.

Horrible - they lied to me about baggage & boarding, even though I specifically spoke to their agents the day before my flight about my issue. When I showed up they did not let me board and stranded me at my airport until I bought a new flight with money I did not have to spend.

The experience was great and much better than the flight going out. of course I was in first class but the service was excellent

Comfort of seats, ease of boarding. Food selection could be better

Food options were limited which is absolutely embarrassing for a Flight of this size The staff did not come around as much and I am not accustomed to such poor service from American Airlines Drinks I believe were limited to soda and water

Because I can’t stand very long in one place, I was allowed to reword.

Crew were attentive and friendly. Flight was smooth and early! I enjoyed the less crowded plane. Thank you!

We are gluten free, there were not any available complimentary gluten free options.

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

9 hours of delay!! Was not able to check my luggage that I paid for!!!

Frontier won’t help you at the airport without paying $25. Carry on was $75. Then you get on the plain and every beverage or snack is also a charge. Seats are hard and real packed in. I would never fly them again.

The Frontier app wasn’t working. So I could not pay for a carry on the week prior to flying. They charged me 99$ at the gate to carry on a duffle bag.

Plane could have been more on time. More leg room .

Didn't like anything!! Horrible flight. Small seating area and hard seats. Butt was sore after 2 hour flight to Seattle No entertainment or free refreshments No wifi or USB charging receptacles to charge phone entoute like other airliners Luggage rates were 3 times as much as competitors. Difficult to navigate online luggue process to pre pay before flight Overall bad experience WILL NEVER RIDE OR RECOMMEND FRONTIER TO FRIENDS OR FAMILY MEMBERS!!! THIS IS A SHAME!! MOST MESERIBLE FLIGHT OF MY LIFE!! AND I THOUGHT SPIRIT WAS 👎 YOU GOT THEM BEAD HANDS DOWN!!

There were 3 leg for the trip and each leg was delayed by 90 minutes or more. The boarding process takes forever with people waiting on the jetway even though most folks do not have carry-on. The whole process is poorly managed.

Not have to pay for every single item to take a flight. Seating and delays sucked.

Terrible. Seats are bad and the baggage policy is inconsistent

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

Book cheap flights from Ontario to Colorado

Recent round-trip flight deals

8/9sex
nonstopFrontier
2h 20mONT-DEN
8/17sáb
nonstopFrontier
2h 19mDEN-ONT
$60
7/1seg
nonstopFrontier
2h 20mONT-DEN
7/16ter
nonstopFrontier
2h 17mDEN-ONT
$61
7/15seg
nonstopFrontier
2h 20mONT-DEN
7/17qua
nonstopFrontier
2h 19mDEN-ONT
$62
6/26qua
nonstopCitizenPlane
2h 21mONT-DEN
7/1seg
nonstopCitizenPlane
2h 22mDEN-ONT
$105
7/13sáb
1 stopDelta
5h 46mONT-DEN
7/16ter
1 stopDelta
6h 25mDEN-ONT
$196
7/6sáb
1 stopDelta
4h 20mONT-DEN
7/13sáb
1 stopDelta
6h 25mDEN-ONT
$216
8/23sex
1 stopAmerican Airlines
4h 05mONT-DEN
8/25dom
1 stopAmerican Airlines
5h 41mDEN-ONT
$217
8/13ter
1 stopUnited Airlines
6h 00mONT-COS
8/20ter
1 stopUnited Airlines
5h 02mCOS-ONT
$270
8/13ter
2 stopsAmerican Airlines
9h 56mONT-COS
8/20ter
1 stopAmerican Airlines
7h 55mCOS-ONT
$275
7/9ter
1 stopUnited Airlines
6h 44mONT-MTJ
7/25qui
1 stopUnited Airlines
6h 23mMTJ-ONT
$300

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Recent one-way flight deals

6/17seg
nonstopFrontier
2h 20mONT-DEN
$38
7/2ter
nonstopFrontier
2h 20mONT-DEN
$39
8/27ter
1 stopAmerican Airlines
4h 28mONT-DEN
$100
7/2ter
1 stopDelta
5h 24mONT-DEN
$108
7/9ter
1 stopAlaska Airlines
6h 34mONT-DEN
$109
7/10qua
nonstopUnited Airlines
2h 25mONT-DEN
$119
7/7dom
1 stopUnited Airlines
6h 44mONT-MTJ
$133
6/24seg
1 stopDelta
4h 54mONT-DEN
$148
9/11qua
2 stopsAlaska Airlines
11h 24mONT-DEN
$166
6/20qui
1 stopAmerican Airlines
8h 53mONT-COS
$225

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Last minute flights from Ontario to Colorado

Last minute flight, train and bus deals

6/10seg
multi-stopFrontier
24h 48mONT-DEN
6/15sáb
nonstopFrontier
2h 20mDEN-ONT
$125
6/13qui
nonstopFrontier
2h 20mONT-DEN
6/15sáb
nonstopFrontier
2h 20mDEN-ONT
$127
6/11ter
multi-stopUnited Airlines
11h 48mONT-DEN
6/18ter
multi-stopUnited Airlines
7h 45mDEN-ONT
$566
6/9dom
multi-stopUnited Airlines
26h 00mONT-DEN
7/13sáb
multi-stopUnited Airlines
7h 15mDEN-ONT
$575
6/9dom
multi-stopAmerican Airlines
3h 36mONT-DRO
6/16dom
multi-stopAmerican Airlines
3h 25mDRO-ONT
$587
6/9dom
multi-stopAmerican Airlines
3h 36mONT-DRO
6/16dom
multi-stopAmerican Airlines
9h 10mDRO-ONT
$592
6/13qui
multi-stopAlaska Airlines
11h 38mONT-DEN
6/17seg
multi-stopAlaska Airlines
7h 11mDEN-ONT
$679
6/9dom
multi-stopAlaska Airlines
9h 50mONT-DEN
10/8ter
multi-stopAlaska Airlines
13h 08mDEN-ONT
$732
6/12qua
multi-stopVolaris
33h 57mONT-DEN
6/17seg
multi-stopVolaris
34h 09mDEN-ONT
$1,302
6/13qui
multi-stopVolaris
8h 27mONT-DEN
6/15sáb
multi-stopVolaris
11h 42mDEN-ONT
$1,324

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Ontario - Colorado Flights

Departure:

Ontario (ONT)United States

Return flight deals:

Colorado - Ontario

Cabin classes:

$648
$487
$559
$75