$74+ 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 5/17. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
Apr 18 — Apr 251
Round-trip
1 adult, Economy
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Find cheap flights from Ontario to Colorado with Cheapflights
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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 March 19, 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 March 19, 2026.
This Super.com deal was found by Cheapflights users on 3/18. 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.
Wed 4/86:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Tue 4/1410:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/18![Frontier logo]()
$87
This Cheapflightsfares deal was found by Cheapflights users on 3/17. 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 4/2012:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Tue 4/2810:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/17![Frontier logo]()
$88
This Super.com deal was found by Cheapflights users on 3/13. 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.
Tue 4/1412:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Sat 4/1810:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/13![Frontier logo]()
$89
This Frontier deal was found by Cheapflights users on 3/13. 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.
Tue 4/2812:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Sat 5/210:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/13![Frontier logo]()
$90
This Super.com deal was found by Cheapflights users on 3/18. 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 4/305:43 pm
ONT
- DEN
Nonstop2h 25m
Frontier
Tue 5/58:41 am
DEN
- ONT
Nonstop2h 24m
Frontier
Deal found 3/18![Frontier logo]()
$92
This Cheapflightsfares deal was found by Cheapflights users on 3/17. 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.
Fri 4/106:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Tue 4/1410:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/17![Frontier logo]()
$93
This Cheapflightsfares deal was found by Cheapflights users on 3/16. 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 4/3012:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Tue 5/510:29 pm
DEN
- ONT
Nonstop2h 20m
Frontier
Deal found 3/16![Frontier logo]()
$94
This Frontier deal was found by Cheapflights users on 3/14. 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.
Tue 4/76:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Tue 4/1410:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/14![Frontier logo]()
$95
This Kiwi.com deal was found by Cheapflights users on 3/17. 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 4/1612:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Mon 4/2010:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/17![Frontier logo]()
$97
This Cheapflightsfares deal was found by Cheapflights users on 3/17. 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 4/96:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Mon 4/1310:30 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/17![Frontier logo]()
$98
This Super.com deal was found by Cheapflights users on 3/15. 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 4/1312:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Tue 4/2110:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/15![Frontier logo]()
$99
This Frontier deal was found by Cheapflights users on 3/15. 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.
Tue 5/56:00 am
ONT
- DEN
Nonstop2h 22m
Frontier
Wed 5/208:41 am
DEN
- ONT
Nonstop2h 24m
Frontier
Deal found 3/15![Frontier logo]()
$100
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 March 19, 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 March 19, 2026.
This Southwest deal was found by Cheapflights users on 3/16. 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 6/43:40 pm
ONT
- DEN
1 stop4h 20m
Southwest
Tue 6/92:40 pm
DEN
- ONT
2 stops6h 35m
Southwest
Deal found 3/16![Southwest logo]()
$228
This Delta deal was found by Cheapflights users on 3/16. 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 5/284:57 pm
ONT
- DEN
1 stop4h 43m
Delta
Mon 6/15:30 am
DEN
- ONT
1 stop4h 23m
Delta
Deal found 3/16![Delta logo]()
$237
This Alaska Airlines deal was found by Cheapflights users on 3/18. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/215:49 pm
ONT
- DEN
1 stop16h 01m
Alaska Airlines
Tue 4/286:00 am
DEN
- ONT
2 stops9h 19m
Alaska Airlines
Deal found 3/18![Alaska Airlines logo]()
$281
This United Airlines deal was found by Cheapflights users on 3/16. 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 4/185:10 am
ONT
- DEN
Nonstop2h 22m
United Airlines
Tue 4/217:10 pm
DEN
- ONT
Nonstop2h 26m
United Airlines
Deal found 3/16![United Airlines logo]()
$287
This Southwest deal was found by Cheapflights users on 3/15. 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 4/111:20 pm
ONT
- COS
1 stop6h 25m
Southwest
Mon 4/135:20 pm
COS
- ONT
1 stop6h 20m
Southwest
Deal found 3/15![Southwest logo]()
$241
This United Airlines deal was found by Cheapflights users on 3/16. 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 4/65:10 am
ONT
- DEN
Nonstop2h 22m
United Airlines
Sat 4/115:15 am
DEN
- ONT
1 stop8h 05m
United Airlines
Deal found 3/16![United Airlines logo]()
$297
This Alaska Airlines deal was found by Cheapflights users on 3/14. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 5/56:00 am
ONT
- DEN
1 stop9h 02m
Alaska Airlines
Wed 5/68:00 am
DEN
- ONT
2 stops16h 48m
Alaska Airlines
Deal found 3/14![Alaska Airlines logo]()
$315
This United Airlines deal was found by Cheapflights users on 3/13. 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 4/181:34 pm
ONT
- DEN
Nonstop2h 22m
United Airlines
Mon 4/207:10 pm
DEN
- ONT
Nonstop2h 26m
United Airlines
Deal found 3/13![United Airlines logo]()
$298
This United Airlines deal was found by Cheapflights users on 3/15. 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 5/71:40 pm
ONT
- DEN
Nonstop2h 22m
United Airlines
Mon 5/117:10 pm
DEN
- ONT
Nonstop2h 26m
United Airlines
Deal found 3/15![United Airlines logo]()
$311
This Delta deal was found by Cheapflights users on 3/17. 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 8/145:05 pm
ONT
- COS
1 stop4h 24m
Delta
Mon 8/175:55 pm
COS
- ONT
1 stop6h 49m
Delta
Deal found 3/17![Delta logo]()
$383
This Southwest deal was found by Cheapflights users on 3/16. 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 6/88:45 pm
ONT
- COS
1 stop3h 35m
Southwest
Sat 6/134:50 pm
COS
- ONT
2 stops7h 00m
Southwest
Deal found 3/16![Southwest logo]()
$372
This United Airlines deal was found by Cheapflights users on 3/18. 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 4/171:43 pm
ONT
- DRO
1 stop5h 56m
United Airlines
Tue 4/2110:30 am
DRO
- ONT
2 stops8h 32m
United Airlines
Deal found 3/18![United Airlines logo]()
$325
This Delta deal was found by Cheapflights users on 3/14. 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.
Sat 8/225:05 pm
ONT
- COS
1 stop4h 24m
Delta
Sun 8/305:55 pm
COS
- ONT
1 stop6h 49m
Delta
Deal found 3/14![Delta logo]()
$411
This Southwest deal was found by Cheapflights users on 3/14. 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 7/215:15 am
ONT
- COS
1 stop5h 20m
Southwest
Mon 7/276:40 am
COS
- ONT
1 stop5h 40m
Southwest
Deal found 3/14![Southwest logo]()
$375
This United Airlines deal was found by Cheapflights users on 3/16. 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 4/295:10 am
ONT
- DRO
1 stop4h 44m
United Airlines
Sat 5/27:00 am
DRO
- ONT
1 stop6h 38m
United Airlines
Deal found 3/16![United Airlines logo]()
$326
This Southwest deal was found by Cheapflights users on 3/15. 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
Sat 8/87:30 am
COS
- ONT
2 stops8h 45m
Southwest
Deal found 3/15![Southwest logo]()
$385
This United Airlines deal was found by Cheapflights users on 3/18. 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 4/285:10 am
ONT
- MTJ
1 stop6h 31m
United Airlines
Wed 4/297:15 am
MTJ
- ONT
1 stop6h 21m
United Airlines
Deal found 3/18![United Airlines logo]()
$329
This United Airlines deal was found by Cheapflights users on 3/15. 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 8/251:18 pm
ONT
- DRO
1 stop6h 36m
United Airlines
Tue 9/17:00 am
DRO
- ONT
1 stop6h 38m
United Airlines
Deal found 3/15![United Airlines logo]()
$330
This Southwest deal was found by Cheapflights users on 3/17. 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.
Fri 8/148:00 am
ONT
- COS
2 stops6h 40m
Southwest
Mon 8/176:30 am
COS
- ONT
2 stops5h 55m
Southwest
Deal found 3/17![Southwest logo]()
$409
This United Airlines deal was found by Cheapflights users on 3/18. 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 4/285:10 am
ONT
- COS
1 stop4h 55m
United Airlines
Wed 4/297:00 am
COS
- ONT
1 stop6h 36m
United Airlines
Deal found 3/18![United Airlines logo]()
$332
This United Airlines deal was found by Cheapflights users on 3/18. 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 4/285:10 am
ONT
- DRO
1 stop6h 24m
United Airlines
Sat 5/211:41 am
DRO
- ONT
2 stops12h 18m
United Airlines
Deal found 3/18![United Airlines logo]()
$333
This United Airlines deal was found by Cheapflights users on 3/14. 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 4/31:43 pm
ONT
- MTJ
1 stop5h 37m
United Airlines
Sat 4/44:06 pm
MTJ
- ONT
1 stop7h 39m
United Airlines
Deal found 3/14![United Airlines logo]()
$341
This United Airlines deal was found by Cheapflights users on 3/17. 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 4/15:10 am
ONT
- MTJ
1 stop6h 31m
United Airlines
Sun 4/54:05 pm
MTJ
- ONT
1 stop7h 40m
United Airlines
Deal found 3/17![United Airlines logo]()
$341
This United Airlines deal was found by Cheapflights users on 3/16. 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 3/315:10 am
ONT
- MTJ
1 stop6h 31m
United Airlines
Sat 4/44:06 pm
MTJ
- ONT
1 stop7h 39m
United Airlines
Deal found 3/16![United Airlines logo]()
$341
This United Airlines deal was found by Cheapflights users on 3/15. 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 4/31:43 pm
ONT
- MTJ
1 stop5h 37m
United Airlines
Sun 4/54:05 pm
MTJ
- ONT
1 stop7h 40m
United Airlines
Deal found 3/15![United Airlines logo]()
$341
This United Airlines deal was found by Cheapflights users on 3/14. 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 4/141:34 pm
ONT
- GJT
1 stop6h 25m
United Airlines
Sat 4/187:01 am
GJT
- ONT
1 stop6h 37m
United Airlines
Deal found 3/14![United Airlines logo]()
$341
This United Airlines deal was found by Cheapflights users on 3/14. 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 4/25:10 am
ONT
- MTJ
1 stop6h 31m
United Airlines
Sat 4/43:37 pm
MTJ
- ONT
2 stops8h 08m
United Airlines
Deal found 3/14![United Airlines logo]()
$346
This United Airlines deal was found by Cheapflights users on 3/16. 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 3/3111:05 am
ONT
- DRO
2 stops8h 49m
United Airlines
Sat 4/43:23 pm
DRO
- ONT
2 stops8h 22m
United Airlines
Deal found 3/16![United Airlines logo]()
$350
This United Airlines deal was found by Cheapflights users on 3/14. 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 4/116:00 am
ONT
- DRO
2 stops10h 05m
United Airlines
Sat 4/183:23 pm
DRO
- ONT
2 stops8h 22m
United Airlines
Deal found 3/14![United Airlines logo]()
$352
This United Airlines deal was found by Cheapflights users on 3/18. 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.
Sun 5/175:00 am
ONT
- MTJ
1 stop6h 41m
United Airlines
Wed 5/207:00 am
MTJ
- ONT
1 stop6h 38m
United Airlines
Deal found 3/18![United Airlines logo]()
$355
Last-minute flights from Ontario to ColoradoDiscover last-minute flight deals from Ontario to Colorado. Data last updated March 19, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to Colorado. Data last updated March 19, 2026 and is based on user searches.
This Frontier deal was found by Cheapflights users on 3/14. 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.
Tue 4/76:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Wed 4/2210:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/14![Frontier logo]()
$95
This Super.com deal was found by Cheapflights users on 3/18. 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.
Wed 4/86:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Tue 4/1410:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/18![Frontier logo]()
$87
This Cheapflightsfares deal was found by Cheapflights users on 3/17. 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 4/96:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Mon 4/1310:30 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/17![Frontier logo]()
$98
This Cheapflightsfares deal was found by Cheapflights users on 3/17. 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.
Fri 4/106:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Tue 4/1410:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/17![Frontier logo]()
$93
This United Airlines deal was found by Cheapflights users on 3/17. 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 4/115:10 am
ONT
- COS
1 stop6h 26m
United Airlines
Sat 4/255:13 pm
COS
- ONT
1 stop4h 23m
United Airlines
Deal found 3/17![United Airlines logo]()
$237
This Super.com deal was found by Cheapflights users on 3/15. 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 4/1312:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Tue 4/2110:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/15![Frontier logo]()
$99
This Super.com deal was found by Cheapflights users on 3/13. 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.
Tue 4/1412:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Sat 4/1810:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/13![Frontier logo]()
$89
This Kiwi.com deal was found by Cheapflights users on 3/17. 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 4/1612:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Mon 4/2010:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/17![Frontier logo]()
$97
This Frontier deal was found by Cheapflights users on 3/17. 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 4/2012:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Sat 4/2510:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/17![Frontier logo]()
$88
This Cheapflightsfares deal was found by Cheapflights users on 3/16. 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 4/2012:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Tue 4/2810:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/16![Frontier logo]()
$100
This Frontier deal was found by Cheapflights users on 3/13. 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.
Tue 4/2812:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Sat 5/210:29 pm
DEN
- ONT
Nonstop2h 26m
Frontier
Deal found 3/13![Frontier logo]()
$90
This Super.com deal was found by Cheapflights users on 3/18. 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 4/305:43 pm
ONT
- DEN
Nonstop2h 25m
Frontier
Tue 5/58:41 am
DEN
- ONT
Nonstop2h 24m
Frontier
Deal found 3/18![Frontier logo]()
$92
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 March 19, 2026.
Search for one-way flight options from Ontario to Colorado. Find affordable one-way fares based on user searches. Data last updated March 19, 2026.
This Frontier deal was found by Cheapflights users on 3/15. 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.
Sun 5/176:00 am
ONT
- DEN
Nonstop2h 22m
Frontier
Deal found 3/15![Frontier logo]()
$74
This Cheapflightsfares deal was found by Cheapflights users on 3/16. 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 5/236:00 am
ONT
- DEN
Nonstop2h 22m
Frontier
Deal found 3/16![Frontier logo]()
$76
This Super.com deal was found by Cheapflights users on 3/15. 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 5/146:00 am
ONT
- DEN
Nonstop2h 22m
Frontier
Deal found 3/15![Frontier logo]()
$78
This CheapOair deal was found by Cheapflights users on 3/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 4/2612:59 am
ONT
- DEN
Nonstop2h 16m
Frontier
Deal found 3/16![Frontier logo]()
$79
This Super.com deal was found by Cheapflights users on 3/14. 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 4/96:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Deal found 3/14![Frontier logo]()
$80
This Cheapflightsfares deal was found by Cheapflights users on 3/15. 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 5/286:00 am
ONT
- DEN
Nonstop2h 22m
Frontier
Deal found 3/15![Frontier logo]()
$81
This CheapOair deal was found by Cheapflights users on 3/16. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/66:20 am
ONT
- DEN
Nonstop2h 23m
Frontier
Deal found 3/16![Frontier logo]()
$82
This Cheapflightsfares deal was found by Cheapflights users on 3/13. 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 5/211:44 am
ONT
- DEN
1 stop11h 35m
Frontier
Deal found 3/13![Frontier logo]()
$86
This Kiwi.com deal was found by Cheapflights users on 3/13. 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 4/1511:44 am
ONT
- DEN
1 stop11h 35m
Frontier
Deal found 3/13![Frontier logo]()
$88
This Super.com deal was found by Cheapflights users on 3/16. 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.
Fri 4/109:02 pm
ONT
- DEN
1 stop5h 57m
Frontier
Deal found 3/16![Frontier logo]()
$89
This Frontier deal was found by Cheapflights users on 3/13. 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.
Tue 4/148:15 am
ONT
- DEN
1 stop8h 25m
Frontier
Deal found 3/13![Frontier logo]()
$90
This Booking.com deal was found by Cheapflights users on 3/16. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/218:15 am
ONT
- DEN
1 stop8h 25m
Frontier
Deal found 3/16![Frontier logo]()
$91
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 March 19, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $87 (Super.com) |
One-way from | $74 (Frontier) |
Popular in | March |
Cheapest in | September |
Average price | $243 |
Good round-trip deal | $253 or less |
Good one-way deal | $154 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 March 19, 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
Thu 6/4
3:40 pm-9:00 pm
1 stop4h 20m
Denver Intl
Tue 6/9
2:40 pm-8:15 pm
2 stops6h 35m
$228
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Thu 5/28
4:57 pm-10:40 pm
1 stop4h 43m
Denver Intl
Mon 6/1
5:30 am-8:53 am
1 stop4h 23m
$237
OntarioColorado Springs
ONT - COS
ONTCOS
Ontario
Sat 4/11
1:20 pm-8:45 pm
1 stop6h 25m
Colorado Springs
Mon 4/13
5:20 pm-10:40 pm
1 stop6h 20m
$241
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Tue 4/21
5:49 pm-10:50 am
1 stop16h 01m
Denver Intl
Tue 4/28
6:00 am-2:19 pm
2 stops9h 19m
$281
Quickest round-trip
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Sat 4/18
5:10 am-8:32 am
Nonstop2h 22m
Denver Intl
Tue 4/21
7:10 pm-8:36 pm
Nonstop2h 26m
$287
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Mon 4/6
5:10 am-8:32 am
Nonstop2h 22m
Denver Intl
Sat 4/11
5:15 am-12:20 pm
1 stop8h 05m
$297
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Sat 4/18
1:34 pm-4:56 pm
Nonstop2h 22m
Denver Intl
Mon 4/20
7:10 pm-8:36 pm
Nonstop2h 26m
$298
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Thu 5/7
1:40 pm-5:02 pm
Nonstop2h 22m
Denver Intl
Mon 5/11
7:10 pm-8:36 pm
Nonstop2h 26m
$311
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Tue 5/5
6:00 am-4:02 pm
1 stop9h 02m
Denver Intl
Wed 5/6
8:00 am-11:48 pm
2 stops16h 48m
$315
OntarioDurango
ONT - DRO
ONTDRO
Ontario
Fri 4/17
1:43 pm-8:39 pm
1 stop5h 56m
Durango La Plata County
Tue 4/21
10:30 am-6:02 pm
2 stops8h 32m
$325
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-COS
ONT-DRO
ONT-MTJ
ONT-GJT
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-COS
ONT-DRO
ONT-MTJ
What is the cheapest month to book a flight from Ontario to Colorado?
Currently, August is the cheapest month in which you can book a flight from Ontario to Colorado (average of $45). Flying from Ontario to Colorado in March is currently the most expensive (average of $77). 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 March 19, 2026.
It’s typically best to fly out from Ontario to Colorado in the evening. Doing so could potentially save you 50% on the flight price compared to flying at noon, which is usually more expensive.
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 March 14, 2026.
Travelers seeking maximum savings on their Ontario to Colorado flight should consider departing on Friday afternoons 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.
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 March 19, 2026.
The most flights from ONT to USCO are scheduled on a Monday (10 on average). You will have fewer flight options on Saturday, 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?
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 March 19, 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
Boarding
8.1
Comfort
8.0
Crew
8.6
Entertainment
7.5
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Boarding
8.1
Comfort
8.0
Crew
8.6
Entertainment
7.5
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Boarding
8.1
Comfort
8.0
Crew
8.6
Entertainment
7.5
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Boarding
8.1
Comfort
8.0
Crew
8.6
Entertainment
7.5
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Boarding
8.1
Comfort
8.0
Crew
8.6
Entertainment
7.5
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Overall
8.0
Boarding
8.1
Comfort
8.0
Crew
8.6
Entertainment
7.5
Food
7.0
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 March 19, 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 March 19, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$62 | Average$160 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$109 | Average$272 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$135 | Average$350 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$144 | Average$314 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$211 | Average$357 | FlexibilityNo cancel fee | On-time71% |