$54+ Cheap flights from Ontario (ONT) to Colorado
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 8/17. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
Aug 25 — Sep 11
Round-trip
1 adult, Economy
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Find cheap flights from Ontario to Colorado with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
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Cheapest flights from Ontario to ColoradoExplore the most affordable flight options available from Ontario to Colorado. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 26, 2026.
Explore the most affordable flight options available from Ontario to Colorado. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 26, 2026.
This Frontier deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/192:55 pm
ONT
- DEN
Nonstop2h 22m
Frontier
Thu 10/2210:34 pm
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 7/25![Frontier logo]()
$105
This Cheapflightsfares deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/296:15 am
ONT
- DEN
Nonstop2h 26m
Frontier
Mon 11/29:15 am
DEN
- ONT
Nonstop2h 28m
Frontier
Deal found 7/23![Frontier logo]()
$106
This Frontier deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/156:00 am
ONT
- DEN
Nonstop2h 24m
Frontier
Sat 8/228:45 am
DEN
- ONT
Nonstop2h 19m
Frontier
Deal found 7/21![Frontier logo]()
$108
This Frontier deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/116:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Fri 9/1110:34 pm
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 7/23![Frontier logo]()
$110
This Cheapflightsfares deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/146:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Thu 9/1710:34 pm
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 7/22![Frontier logo]()
$113
This Frontier deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/126:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Thu 9/1710:34 pm
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 7/21![Frontier logo]()
$115
This Cheapflightsfares deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/310:49 am
ONT
- DEN
Nonstop2h 21m
Frontier
Sun 9/610:29 pm
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 7/22![Frontier logo]()
$122
This Cheapflightsfares deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/57:56 pm
ONT
- DEN
Nonstop2h 25m
Frontier
Mon 9/78:45 am
DEN
- ONT
Nonstop2h 19m
Frontier
Deal found 7/23![Frontier logo]()
$123
This Kiwi.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/187:56 pm
ONT
- DEN
Nonstop2h 25m
Frontier
Tue 8/2510:49 pm
DEN
- ONT
2 stops16h 14m
Frontier
Deal found 7/22![Frontier logo]()
$127
This United Airlines deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/215:00 am
ONT
- DRO
1 stop4h 51m
United Airlines
Sat 10/243:24 pm
DRO
- ONT
1 stop6h 34m
United Airlines
Deal found 7/25![United Airlines logo]()
$308
This American Airlines deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/126:15 am
ONT
- GJT
1 stop4h 22m
American Airlines
Sat 8/158:30 am
GJT
- ONT
1 stop4h 33m
American Airlines
Deal found 7/22![American Airlines logo]()
$309
This United Airlines deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/185:00 am
ONT
- GJT
1 stop4h 44m
United Airlines
Mon 8/249:24 am
GJT
- ONT
2 stops11h 37m
United Airlines
Deal found 7/21![United Airlines logo]()
$314
Best flights from Ontario to ColoradoDiscover carefully curated flight deals from Ontario to Colorado that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 26, 2026.
Discover carefully curated flight deals from Ontario to Colorado that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated July 26, 2026.
This Southwest deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/291:50 pm
ONT
- DEN
Nonstop2h 15m
Southwest
Sat 10/35:45 am
DEN
- ONT
2 stops6h 25m
Southwest
Deal found 7/23![Southwest logo]()
$172
This United Airlines deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/175:00 am
ONT
- DEN
Nonstop2h 21m
United Airlines
Thu 8/207:30 pm
DEN
- ONT
Nonstop2h 23m
United Airlines
Deal found 7/22![United Airlines logo]()
$237
This Delta deal was found by Cheapflights users on 7/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/125:05 pm
ONT
- GJT
1 stop3h 51m
Delta
Sat 8/157:41 am
GJT
- ONT
1 stop5h 35m
Delta
Deal found 7/26![Delta logo]()
$334
This Southwest deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/1210:35 am
ONT
- DEN
1 stop4h 25m
Southwest
Wed 9/169:00 am
DEN
- ONT
1 stop6h 05m
Southwest
Deal found 7/25![Southwest logo]()
$177
This Southwest deal was found by Cheapflights users on 7/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/55:50 am
ONT
- DEN
2 stops7h 35m
Southwest
Thu 9/108:10 am
DEN
- ONT
1 stop6h 15m
Southwest
Deal found 7/26![Southwest logo]()
$182
This Southwest deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/1912:30 pm
ONT
- DEN
1 stop6h 20m
Southwest
Wed 8/262:00 pm
DEN
- ONT
1 stop4h 35m
Southwest
Deal found 7/22![Southwest logo]()
$187
This United Airlines deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/205:00 am
ONT
- DEN
Nonstop2h 21m
United Airlines
Thu 8/277:30 pm
DEN
- ONT
Nonstop2h 23m
United Airlines
Deal found 7/23![United Airlines logo]()
$237
This United Airlines deal was found by Cheapflights users on 7/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/235:00 am
ONT
- DEN
Nonstop2h 17m
United Airlines
Thu 11/2611:15 am
DEN
- ONT
Nonstop2h 18m
United Airlines
Deal found 7/26![United Airlines logo]()
$243
This Southwest deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/144:55 pm
ONT
- DEN
1 stop4h 20m
Southwest
Mon 12/218:30 am
DEN
- ONT
Nonstop2h 25m
Southwest
Deal found 7/25![Southwest logo]()
$247
This Delta deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/245:15 pm
ONT
- COS
1 stop4h 10m
Delta
Wed 9/308:15 am
COS
- ONT
1 stop4h 59m
Delta
Deal found 7/25![Delta logo]()
$377
This United Airlines deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/185:00 am
ONT
- GJT
1 stop4h 44m
United Airlines
Mon 8/249:24 am
GJT
- ONT
2 stops11h 37m
United Airlines
Deal found 7/21![United Airlines logo]()
$314
This Southwest deal was found by Cheapflights users on 7/26. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/205:45 pm
ONT
- DEN
1 stop3h 55m
Southwest
Mon 8/244:10 pm
DEN
- ONT
2 stops6h 15m
Southwest
Deal found 7/26![Southwest logo]()
$262
This Delta deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/245:15 pm
ONT
- COS
1 stop4h 10m
Delta
Tue 9/296:11 pm
COS
- ONT
1 stop6h 36m
Delta
Deal found 7/22![Delta logo]()
$377
This United Airlines deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/215:00 am
ONT
- DRO
1 stop6h 32m
United Airlines
Sat 10/31:37 pm
DRO
- ONT
2 stops10h 14m
United Airlines
Deal found 7/25![United Airlines logo]()
$314
This United Airlines deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/215:00 am
ONT
- DRO
1 stop6h 32m
United Airlines
Fri 9/251:37 pm
DRO
- ONT
2 stops7h 54m
United Airlines
Deal found 7/25![United Airlines logo]()
$314
This Southwest deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/55:50 am
ONT
- DEN
2 stops7h 35m
Southwest
Mon 9/79:45 am
DEN
- ONT
1 stop4h 40m
Southwest
Deal found 7/25![Southwest logo]()
$310
This United Airlines deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/225:00 am
ONT
- MTJ
1 stop6h 45m
United Airlines
Thu 8/273:24 pm
MTJ
- ONT
1 stop6h 29m
United Airlines
Deal found 7/22![United Airlines logo]()
$317
This United Airlines deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/221:18 pm
ONT
- MTJ
1 stop6h 07m
United Airlines
Wed 8/263:24 pm
MTJ
- ONT
1 stop6h 29m
United Airlines
Deal found 7/22![United Airlines logo]()
$317
This Delta deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/25:15 pm
ONT
- COS
1 stop4h 10m
Delta
Mon 10/56:11 pm
COS
- ONT
1 stop6h 36m
Delta
Deal found 7/22![Delta logo]()
$467
This Southwest deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/191:00 pm
ONT
- COS
1 stop6h 40m
Southwest
Thu 9/243:00 pm
COS
- ONT
1 stop6h 25m
Southwest
Deal found 7/25![Southwest logo]()
$353
This United Airlines deal was found by Cheapflights users on 7/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 1/91:00 pm
ONT
- MTJ
1 stop6h 09m
United Airlines
Sat 1/163:20 pm
MTJ
- ONT
1 stop6h 00m
United Airlines
Deal found 7/24![United Airlines logo]()
$323
This Southwest deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/242:40 pm
ONT
- COS
2 stops6h 05m
Southwest
Tue 9/297:20 am
COS
- ONT
2 stops6h 20m
Southwest
Deal found 7/23![Southwest logo]()
$363
This United Airlines deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/85:00 am
ONT
- DRO
1 stop6h 28m
United Airlines
Tue 8/115:15 am
DRO
- ONT
2 stops7h 57m
United Airlines
Deal found 7/22![United Airlines logo]()
$344
This Southwest deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/66:20 am
ONT
- COS
2 stops8h 15m
Southwest
Sun 10/116:10 am
COS
- ONT
2 stops7h 05m
Southwest
Deal found 7/22![Southwest logo]()
$387
This United Airlines deal was found by Cheapflights users on 7/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/141:29 pm
ONT
- DRO
1 stop7h 17m
United Airlines
Wed 11/181:35 pm
DRO
- ONT
2 stops7h 40m
United Airlines
Deal found 7/24![United Airlines logo]()
$394
This United Airlines deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/135:00 am
ONT
- DRO
1 stop6h 32m
United Airlines
Thu 8/201:34 pm
DRO
- ONT
2 stops7h 27m
United Airlines
Deal found 7/23![United Airlines logo]()
$394
This Southwest deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/58:35 am
ONT
- COS
2 stops6h 25m
Southwest
Mon 8/105:30 am
COS
- ONT
1 stop6h 55m
Southwest
Deal found 7/21![Southwest logo]()
$470
This United Airlines deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/141:29 pm
ONT
- GJT
1 stop7h 30m
United Airlines
Tue 11/173:11 pm
GJT
- ONT
1 stop6h 40m
United Airlines
Deal found 7/25![United Airlines logo]()
$399
This United Airlines deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/195:00 am
ONT
- GJT
1 stop4h 44m
United Airlines
Wed 8/263:12 pm
GJT
- ONT
1 stop6h 41m
United Airlines
Deal found 7/21![United Airlines logo]()
$399
This United Airlines deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/181:18 pm
ONT
- GJT
1 stop6h 17m
United Airlines
Tue 8/253:12 pm
GJT
- ONT
1 stop6h 41m
United Airlines
Deal found 7/21![United Airlines logo]()
$399
Last-minute flights from Ontario to ColoradoDiscover last-minute flight deals from Ontario to Colorado. Data last updated July 26, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to Colorado. Data last updated July 26, 2026 and is based on user searches.
This American Airlines deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/126:15 am
ONT
- GJT
1 stop4h 22m
American Airlines
Sat 8/158:30 am
GJT
- ONT
1 stop4h 33m
American Airlines
Deal found 7/22![American Airlines logo]()
$309
This Kissandfly.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kissandfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/131:06 pm
ONT
- DEN
1 stop5h 55m
Frontier
Mon 8/178:45 am
DEN
- ONT
Nonstop2h 19m
Frontier
Deal found 7/22![Frontier logo]()
$129
This Kiwi.com deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/1310:49 am
ONT
- DEN
Nonstop2h 21m
Frontier
Tue 8/187:00 am
DEN
- ONT
1 stop13h 01m
Frontier
Deal found 7/23![Frontier logo]()
$132
This Frontier deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/156:00 am
ONT
- DEN
Nonstop2h 24m
Frontier
Sat 8/228:45 am
DEN
- ONT
Nonstop2h 19m
Frontier
Deal found 7/21![Frontier logo]()
$108
This Kiwi.com deal was found by Cheapflights users on 7/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/156:00 am
ONT
- DEN
Nonstop2h 24m
Frontier
Tue 8/187:00 am
DEN
- ONT
1 stop13h 01m
Frontier
Deal found 7/24![Frontier logo]()
$131
This Kiwi.com deal was found by Cheapflights users on 7/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/178:58 am
ONT
- DEN
2 stops24h 05m
Frontier
Sat 8/2210:29 pm
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 7/24![Frontier logo]()
$128
This Kiwi.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/187:56 pm
ONT
- DEN
Nonstop2h 25m
Frontier
Tue 8/2510:49 pm
DEN
- ONT
2 stops16h 14m
Frontier
Deal found 7/22![Frontier logo]()
$127
This Kiwi.com deal was found by Cheapflights users on 7/23. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/183:13 pm
ONT
- DEN
2 stops11h 35m
Frontier
Sat 8/2210:29 pm
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 7/23![Frontier logo]()
$138
This Kiwi.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/187:56 pm
ONT
- DEN
Nonstop2h 25m
Frontier
Mon 8/2412:47 pm
DEN
- ONT
1 stop4h 35m
Frontier
Deal found 7/22![Frontier logo]()
$143
This United Airlines deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/185:00 am
ONT
- GJT
1 stop4h 44m
United Airlines
Mon 8/249:24 am
GJT
- ONT
2 stops11h 37m
United Airlines
Deal found 7/21![United Airlines logo]()
$314
This Kiwi.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/197:56 pm
ONT
- DEN
Nonstop2h 25m
Frontier
Wed 8/267:00 am
DEN
- ONT
1 stop13h 01m
Frontier
Deal found 7/22![Frontier logo]()
$125
This Kiwi.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/196:00 am
ONT
- DEN
Nonstop2h 24m
Frontier
Thu 8/2712:47 pm
DEN
- ONT
1 stop4h 35m
Frontier
Deal found 7/22![Frontier logo]()
$144
One-way flights from Ontario to ColoradoSearch for one-way flight options from Ontario to Colorado. Find affordable one-way fares based on user searches. Data last updated July 26, 2026.
Search for one-way flight options from Ontario to Colorado. Find affordable one-way fares based on user searches. Data last updated July 26, 2026.
This Super.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/176:00 am
ONT
- DEN
Nonstop2h 24m
Frontier
Deal found 7/22![Frontier logo]()
$54
This Super.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 11/196:15 am
ONT
- DEN
Nonstop2h 26m
Frontier
Deal found 7/22![Frontier logo]()
$71
This Cheapflightsfares deal was found by Cheapflights users on 7/25. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/176:15 am
ONT
- DEN
Nonstop2h 20m
Frontier
Deal found 7/25![Frontier logo]()
$72
This Trip.com deal was found by Cheapflights users on 7/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/266:15 am
ONT
- DEN
Nonstop2h 20m
Frontier
Deal found 7/24![Frontier logo]()
$75
This United Airlines deal was found by Cheapflights users on 7/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/265:00 am
ONT
- DEN
Nonstop2h 21m
United Airlines
Deal found 7/24![United Airlines logo]()
$79
This Kiwi.com deal was found by Cheapflights users on 7/24. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/83:13 pm
ONT
- DEN
2 stops25h 19m
Frontier
Deal found 7/24![Frontier logo]()
$86
This Southwest deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/194:45 pm
ONT
- DEN
1 stop4h 05m
Southwest
Deal found 7/22![Southwest logo]()
$89
This Kiwi.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/193:13 pm
ONT
- DEN
2 stops11h 35m
Frontier
Deal found 7/22![Frontier logo]()
$91
This Cheapflightsfares deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 11/142:35 pm
ONT
- DEN
Nonstop2h 22m
Frontier
Deal found 7/21![Frontier logo]()
$92
This Kiwi.com deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/118:58 am
ONT
- DEN
2 stops24h 05m
Frontier
Deal found 7/22![Frontier logo]()
$97
This American Airlines deal was found by Cheapflights users on 7/21. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/156:15 am
ONT
- COS
2 stops15h 38m
American Airlines
Deal found 7/21![American Airlines logo]()
$156
This United Airlines deal was found by Cheapflights users on 7/22. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/155:00 am
ONT
- MTJ
1 stop6h 45m
United Airlines
Deal found 7/22![United Airlines logo]()
$159
Find flight deals from Ontario to Colorado
Keep the following information in mind while searching for Ontario to Colorado flight deals. Data was last updated July 26, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $105 (Frontier) |
One-way from | $54 (Super.com) |
Popular in | June |
Cheapest in | September |
Average price | $274 |
Good round-trip deal | $296 or less |
Good one-way deal | $190 or less |
Cheapflights Fare Finder
Customize your flight search to find flights from Ontario to Colorado that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 26, 2026.
Use the filters below to find and compare flights from Ontario to Colorado that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Tue 9/29
1:50 pm-5:05 pm
Nonstop2h 15m
Denver Intl
Sat 10/3
5:45 am-11:10 am
2 stops6h 25m
$172
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Sat 9/12
10:35 am-4:00 pm
1 stop4h 25m
Denver Intl
Wed 9/16
9:00 am-2:05 pm
1 stop6h 05m
$177
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Sat 9/5
5:50 am-2:25 pm
2 stops7h 35m
Denver Intl
Thu 9/10
8:10 am-1:25 pm
1 stop6h 15m
$182
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Wed 8/19
12:30 pm-7:50 pm
1 stop6h 20m
Denver Intl
Wed 8/26
2:00 pm-5:35 pm
1 stop4h 35m
$187
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Mon 8/17
5:00 am-8:21 am
Nonstop2h 21m
Denver Intl
Thu 8/20
7:30 pm-8:53 pm
Nonstop2h 23m
$237
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Thu 8/20
5:00 am-8:21 am
Nonstop2h 21m
Denver Intl
Thu 8/27
7:30 pm-8:53 pm
Nonstop2h 23m
$237
Quickest round-trip
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Mon 11/23
5:00 am-8:17 am
Nonstop2h 17m
Denver Intl
Thu 11/26
11:15 am-12:33 pm
Nonstop2h 18m
$243
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Mon 12/14
4:55 pm-10:15 pm
1 stop4h 20m
Denver Intl
Mon 12/21
8:30 am-9:55 am
Nonstop2h 25m
$247
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Thu 8/20
5:45 pm-10:40 pm
1 stop3h 55m
Denver Intl
Mon 8/24
4:10 pm-9:25 pm
2 stops6h 15m
$262
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Sat 9/5
5:50 am-2:25 pm
2 stops7h 35m
Denver Intl
Mon 9/7
9:45 am-1:25 pm
1 stop4h 40m
$310
Showing 1-10 of 60 resultsSorted by cheapest first
Best time to book a flight from Ontario to Colorado
Have a flexible travel schedule? Discover the best time to fly to Colorado from Ontario with our price prediction graph.
ONT-DEN
ONT-GJT
ONT-COS
ONT-DRO
ONT-MTJ
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from Ontario to Colorado
ONT-USCO
ONT-DEN
ONT-GJT
ONT-COS
ONT-DRO
What is the cheapest month to book a flight from Ontario to Colorado?
Currently, February is the cheapest month in which you can book a flight from Ontario to Colorado (average of $178). Flying from Ontario to Colorado in June is currently the most expensive (average of $342). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
What is the cheapest time of day to fly from ONT to CO?
Find hourly flight availability from Ontario to Colorado. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated July 26, 2026.
It’s typically best to fly out from Ontario to Colorado in the evening. Doing so could potentially save you 54% on the flight price compared to flying at noon, which is usually more expensive.
Weekly flight availability from Ontario to Colorado
Explore weekly flight availability from Ontario to Colorado. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated July 26, 2026.
The most flights from ONT to USCO are scheduled on a Monday (14 on average). You will have fewer flight options on Wednesday, which is when the least amount of flights are scheduled (6 on average).
How much does it cost to fly round-trip from Ontario to Colorado?
Airfare is below average for this route at the moment.
Ontario to Colorado flights typically cost between $146 and $312 in October.The cheapest round-trip price found within the last 5 days was $105 on Frontier (Oct 19-Oct 22).
How far ahead should I book a flight from Ontario to Colorado?
The price you pay for your flight from Ontario to Colorado may vary depending on when you book. For the best chance of a lower fare, look to book 68 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.
What is the cheapest day to fly from Ontario to Colorado?
Use this chart to determine the cheapest time to fly round-trip from Ontario to Colorado. Price data was last updated on July 25, 2026.
Travelers seeking maximum savings on their Ontario to Colorado flight should consider departing on Saturday evenings when fares are most often at their lowest. Sunday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
Reviews of airlines servicing Colorado
Get insights into the airlines that provide service to Colorado. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Colorado. Reviews last updated July 26, 2026.
See what other customers who have flown with Southwest,Delta, andUnited Airlines from Ontario to Colorado have to say. Users can see the overall rating for each airline as well as how each is rated in terms of entertainment options, comfort, food, crew/service, and boarding process.
Overall
8.0
Food
7.0
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Food
7.0
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Related info for your journey
Find useful and relevant information for your journey from Ontario to Colorado. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
Browse thousands of different options on Cheapflights for your next trip
Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.
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Alternative routes for Ontario to Colorado
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Colorado by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from Ontario to Colorado by cabin class
Find flights from Ontario to Colorado, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Ontario and Colorado flights
Browse other Ontario and Colorado flight options. Last updated on July 26, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
Ontario to Colorado flights
Consider these flights traveling from Ontario to Colorado.
Top 5 airlines flying from Ontario to Colorado
Discover the top 5 airlines that operate flights from Ontario to Colorado. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated July 26, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$60 | Average$177 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$157 | Average$372 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$157 | Average$334 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$172 | Average$273 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$211 | Average$366 | FlexibilityNo cancel fee | On-time71% |