$33+ 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 10/6. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — DEN
Jun 28 — Jul 51
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 May 29, 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 May 29, 2026.
This Kiwi.com deal was found by Cheapflights users on 5/24. 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.
Thu 8/1310:49 am
ONT
- DEN
Nonstop2h 21m
Frontier
Mon 8/178:45 am
DEN
- ONT
Nonstop2h 19m
Frontier
Deal found 5/24![Frontier logo]()
$122
This Kiwi.com deal was found by Cheapflights users on 5/24. 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 8/1110:49 am
ONT
- DEN
Nonstop2h 21m
Frontier
Wed 8/198:44 am
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 5/24![Frontier logo]()
$124
This Frontier deal was found by Cheapflights users on 5/26. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/56:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Wed 9/2312:32 pm
DEN
- ONT
Nonstop2h 25m
Frontier
Deal found 5/26![Frontier logo]()
$125
This Cheapflightsfares deal was found by Cheapflights users on 5/26. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/2510:50 am
ONT
- DEN
Nonstop2h 19m
Frontier
Wed 9/28:44 am
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 5/26![Frontier logo]()
$126
This Frontier deal was found by Cheapflights users on 5/28. 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
Tue 9/1512:32 pm
DEN
- ONT
Nonstop2h 25m
Frontier
Deal found 5/28![Frontier logo]()
$129
This Frontier deal was found by Cheapflights users on 5/27. 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 8/316:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Tue 9/2210:34 pm
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 5/27![Frontier logo]()
$130
This Frontier deal was found by Cheapflights users on 5/28. 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 9/86:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Sat 9/1212:32 pm
DEN
- ONT
Nonstop2h 25m
Frontier
Deal found 5/28![Frontier logo]()
$131
This Frontier deal was found by Cheapflights users on 5/25. 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.
Tue 9/810:50 am
ONT
- DEN
Nonstop2h 19m
Frontier
Wed 9/3012:32 pm
DEN
- ONT
Nonstop2h 25m
Frontier
Deal found 5/25![Frontier logo]()
$132
This Frontier deal was found by Cheapflights users on 5/26. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/96:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Wed 9/3012:32 pm
DEN
- ONT
Nonstop2h 25m
Frontier
Deal found 5/26![Frontier logo]()
$133
This Cheapflightsfares deal was found by Cheapflights users on 5/28. 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.
Wed 6/246:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Wed 7/18:44 am
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 5/28![Frontier logo]()
$135
This Delta deal was found by Cheapflights users on 5/26. 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.
Sat 8/155:05 pm
ONT
- COS
1 stop4h 23m
Delta
Thu 8/206:16 pm
COS
- ONT
1 stop6h 18m
Delta
Deal found 5/26![Delta logo]()
$197
This United Airlines deal was found by Cheapflights users on 5/24. 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.
Wed 8/195:00 am
ONT
- COS
1 stop7h 17m
United Airlines
Wed 8/265:30 am
COS
- ONT
2 stops7h 42m
United Airlines
Deal found 5/24![United Airlines logo]()
$202
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 May 29, 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 May 29, 2026.
This Southwest deal was found by Cheapflights users on 5/24. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/176:35 pm
ONT
- DEN
1 stop4h 30m
Southwest
Tue 6/236:15 am
DEN
- ONT
1 stop4h 00m
Southwest
Deal found 5/24![Southwest logo]()
$165
This Delta deal was found by Cheapflights users on 5/27. 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
- DEN
1 stop4h 46m
Delta
Mon 8/175:35 am
DEN
- ONT
1 stop4h 13m
Delta
Deal found 5/27![Delta logo]()
$197
This United Airlines deal was found by Cheapflights users on 5/24. 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.
Wed 8/195:00 am
ONT
- COS
1 stop7h 17m
United Airlines
Wed 8/265:30 am
COS
- ONT
2 stops7h 42m
United Airlines
Deal found 5/24![United Airlines logo]()
$202
This Southwest deal was found by Cheapflights users on 5/27. 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 7/154:10 pm
ONT
- DEN
2 stops6h 00m
Southwest
Wed 8/1212:25 pm
DEN
- ONT
1 stop4h 35m
Southwest
Deal found 5/27![Southwest logo]()
$170
This American Airlines deal was found by Cheapflights users on 5/24. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/167:15 pm
ONT
- EGE
2 stops13h 38m
American Airlines
Tue 7/217:50 am
EGE
- ONT
1 stop6h 32m
American Airlines
Deal found 5/24![American Airlines logo]()
$384
This Delta deal was found by Cheapflights users on 5/28. 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.
Tue 10/139:55 am
ONT
- DEN
1 stop4h 14m
Delta
Tue 10/205:40 am
DEN
- ONT
1 stop4h 27m
Delta
Deal found 5/28![Delta logo]()
$197
This Delta deal was found by Cheapflights users on 5/28. 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.
Mon 8/176:00 am
ONT
- DEN
1 stop5h 04m
Delta
Thu 8/207:05 am
DEN
- ONT
1 stop6h 00m
Delta
Deal found 5/28![Delta logo]()
$197
This United Airlines deal was found by Cheapflights users on 5/25. 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 9/235:00 am
ONT
- COS
1 stop4h 44m
United Airlines
Wed 9/301:15 pm
COS
- ONT
2 stops10h 44m
United Airlines
Deal found 5/25![United Airlines logo]()
$230
This Delta deal was found by Cheapflights users on 5/28. 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 8/135:05 pm
ONT
- DEN
1 stop4h 46m
Delta
Thu 8/205:35 am
DEN
- ONT
1 stop4h 13m
Delta
Deal found 5/28![Delta logo]()
$197
This Southwest deal was found by Cheapflights users on 5/28. 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 7/156:35 pm
ONT
- COS
1 stop4h 15m
Southwest
Tue 7/215:10 pm
COS
- ONT
2 stops6h 55m
Southwest
Deal found 5/28![Southwest logo]()
$274
This United Airlines deal was found by Cheapflights users on 5/25. 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 7/225:00 am
ONT
- DEN
Nonstop2h 20m
United Airlines
Tue 7/286:00 am
DEN
- ONT
1 stop7h 12m
United Airlines
Deal found 5/25![United Airlines logo]()
$275
This Delta deal was found by Cheapflights users on 5/28. 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.
Tue 6/306:00 am
ONT
- DEN
1 stop4h 53m
Delta
Tue 7/75:40 am
DEN
- ONT
1 stop4h 07m
Delta
Deal found 5/28![Delta logo]()
$228
This Southwest deal was found by Cheapflights users on 5/25. 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.
Fri 7/178:45 pm
ONT
- COS
1 stop3h 40m
Southwest
Tue 7/217:05 pm
COS
- ONT
1 stop4h 45m
Southwest
Deal found 5/25![Southwest logo]()
$274
This Southwest deal was found by Cheapflights users on 5/28. 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 10/136:15 am
ONT
- DEN
1 stop4h 40m
Southwest
Tue 10/206:30 am
DEN
- ONT
2 stops6h 50m
Southwest
Deal found 5/28![Southwest logo]()
$290
This American Airlines deal was found by Cheapflights users on 5/23. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 6/157:13 pm
ONT
- DRO
1 stop3h 46m
American Airlines
Wed 6/247:25 pm
DRO
- ONT
1 stop3h 32m
American Airlines
Deal found 5/23![American Airlines logo]()
$404
This United Airlines deal was found by Cheapflights users on 5/24. 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 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 5/24![United Airlines logo]()
$351
This United Airlines deal was found by Cheapflights users on 5/27. 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 10/275:00 am
ONT
- COS
1 stop4h 41m
United Airlines
Wed 10/285:13 pm
COS
- ONT
1 stop4h 07m
United Airlines
Deal found 5/27![United Airlines logo]()
$356
This Southwest deal was found by Cheapflights users on 5/25. 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.
Tue 8/181:10 pm
ONT
- DEN
1 stop4h 35m
Southwest
Sat 8/2211:15 am
DEN
- ONT
2 stops7h 45m
Southwest
Deal found 5/25![Southwest logo]()
$328
This American Airlines deal was found by Cheapflights users on 5/25. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/177:13 pm
ONT
- DRO
1 stop3h 46m
American Airlines
Thu 6/256:48 pm
DRO
- ONT
1 stop4h 09m
American Airlines
Deal found 5/25![American Airlines logo]()
$455
This United Airlines deal was found by Cheapflights users on 5/23. 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.
Sun 6/145:00 am
ONT
- DRO
1 stop6h 28m
United Airlines
Wed 6/247:00 am
DRO
- ONT
1 stop6h 47m
United Airlines
Deal found 5/23![United Airlines logo]()
$364
This United Airlines deal was found by Cheapflights users on 5/25. 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.
Tue 6/91:18 pm
ONT
- ASE
1 stop4h 11m
United Airlines
Sat 6/133:25 pm
ASE
- ONT
1 stop6h 21m
United Airlines
Deal found 5/25![United Airlines logo]()
$365
This Delta deal was found by Cheapflights users on 5/26. 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 8/56:00 am
ONT
- DEN
1 stop5h 04m
Delta
Mon 8/1012:54 pm
DEN
- ONT
2 stops10h 51m
Delta
Deal found 5/26![Delta logo]()
$409
This Southwest deal was found by Cheapflights users on 5/27. 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 7/14:10 pm
ONT
- DEN
2 stops5h 55m
Southwest
Tue 7/2811:55 am
DEN
- ONT
2 stops6h 10m
Southwest
Deal found 5/27![Southwest logo]()
$375
This American Airlines deal was found by Cheapflights users on 5/23. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 6/147:13 pm
ONT
- DRO
2 stops13h 41m
American Airlines
Wed 6/247:25 pm
DRO
- ONT
1 stop3h 32m
American Airlines
Deal found 5/23![American Airlines logo]()
$510
This United Airlines deal was found by Cheapflights users on 5/27. 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
- GJT
1 stop6h 38m
United Airlines
Wed 8/197:00 am
GJT
- ONT
1 stop6h 50m
United Airlines
Deal found 5/27![United Airlines logo]()
$405
This American Airlines deal was found by Cheapflights users on 5/26. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 6/1911:59 pm
ONT
- EGE
1 stop8h 54m
American Airlines
Mon 6/227:50 am
EGE
- ONT
2 stops11h 31m
American Airlines
Deal found 5/26![American Airlines logo]()
$587
This United Airlines deal was found by Cheapflights users on 5/24. 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.
Wed 7/85:00 am
ONT
- GJT
1 stop6h 31m
United Airlines
Sat 7/117:00 am
GJT
- ONT
1 stop6h 47m
United Airlines
Deal found 5/24![United Airlines logo]()
$405
This United Airlines deal was found by Cheapflights users on 5/24. 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 6/205:00 am
ONT
- GJT
1 stop6h 31m
United Airlines
Mon 6/221:33 pm
GJT
- ONT
1 stop4h 55m
United Airlines
Deal found 5/24![United Airlines logo]()
$405
This United Airlines deal was found by Cheapflights users on 5/25. 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 8/155:00 am
ONT
- MTJ
1 stop6h 45m
United Airlines
Sat 8/221:42 pm
MTJ
- ONT
2 stops7h 19m
United Airlines
Deal found 5/25![United Airlines logo]()
$410
This United Airlines deal was found by Cheapflights users on 5/27. 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 6/265:00 am
ONT
- MTJ
1 stop6h 34m
United Airlines
Tue 6/307:25 am
MTJ
- ONT
1 stop6h 22m
United Airlines
Deal found 5/27![United Airlines logo]()
$420
Last-minute flights from Ontario to ColoradoDiscover last-minute flight deals from Ontario to Colorado. Data last updated May 29, 2026 and is based on user searches.
Discover last-minute flight deals from Ontario to Colorado. Data last updated May 29, 2026 and is based on user searches.
This American Airlines deal was found by Cheapflights users on 5/25. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 6/97:13 pm
ONT
- DRO
1 stop3h 46m
American Airlines
Tue 6/166:48 pm
DRO
- ONT
1 stop4h 09m
American Airlines
Deal found 5/25![American Airlines logo]()
$249
This Southwest deal was found by Cheapflights users on 5/27. 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 6/164:05 pm
ONT
- DEN
1 stop6h 00m
Southwest
Tue 6/235:05 pm
DEN
- ONT
1 stop4h 15m
Southwest
Deal found 5/27![Southwest logo]()
$165
This Cheapflightsfares deal was found by Cheapflights users on 5/24. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/176:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Tue 6/234:26 pm
DEN
- ONT
1 stop4h 25m
Frontier
Deal found 5/24![Frontier logo]()
$150
This Cheapflightsfares deal was found by Cheapflights users on 5/24. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/176:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Thu 6/257:26 pm
DEN
- ONT
1 stop20h 42m
Frontier
Deal found 5/24![Frontier logo]()
$169
This CheapOair deal was found by Cheapflights users on 5/24. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 6/176:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Mon 6/227:00 am
DEN
- ONT
1 stop11h 52m
Frontier
Deal found 5/24![Frontier logo]()
$171
This Delta deal was found by Cheapflights users on 5/24. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/185:21 pm
ONT
- GJT
1 stop3h 33m
Delta
Tue 6/237:40 am
GJT
- ONT
1 stop5h 30m
Delta
Deal found 5/24![Delta logo]()
$290
This Southwest deal was found by Cheapflights users on 5/25. 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 6/228:45 pm
ONT
- COS
1 stop3h 35m
Southwest
Wed 6/247:55 pm
COS
- ONT
1 stop4h 05m
Southwest
Deal found 5/25![Southwest logo]()
$286
This Cheapflightsfares deal was found by Cheapflights users on 5/25. 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.
Tue 6/236:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Tue 6/308:44 am
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 5/25![Frontier logo]()
$148
This Southwest deal was found by Cheapflights users on 5/26. 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.
Tue 6/236:35 pm
ONT
- COS
1 stop4h 10m
Southwest
Tue 6/307:05 pm
COS
- ONT
1 stop4h 40m
Southwest
Deal found 5/26![Southwest logo]()
$276
This Cheapflightsfares deal was found by Cheapflights users on 5/28. 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.
Wed 6/246:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Wed 7/18:44 am
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 5/28![Frontier logo]()
$135
This American Airlines deal was found by Cheapflights users on 5/27. 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 6/247:13 pm
ONT
- GJT
1 stop3h 30m
American Airlines
Sat 6/278:35 am
GJT
- ONT
1 stop4h 29m
American Airlines
Deal found 5/27![American Airlines logo]()
$271
This Frontier deal was found by Cheapflights users on 5/23. 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.
Sat 6/2710:50 am
ONT
- DEN
Nonstop2h 19m
Frontier
Tue 6/308:44 am
DEN
- ONT
Nonstop2h 21m
Frontier
Deal found 5/23![Frontier logo]()
$183
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 May 29, 2026.
Search for one-way flight options from Ontario to Colorado. Find affordable one-way fares based on user searches. Data last updated May 29, 2026.
This Frontier deal was found by Cheapflights users on 5/24. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/62:55 pm
ONT
- DEN
Nonstop2h 22m
Frontier
Deal found 5/24![Frontier logo]()
$33
This Cheapflightsfares deal was found by Cheapflights users on 5/25. 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.
Wed 8/126:00 am
ONT
- DEN
Nonstop2h 24m
Frontier
Deal found 5/25![Frontier logo]()
$37
This Frontier deal was found by Cheapflights users on 5/24. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/76:00 am
ONT
- DEN
Nonstop2h 24m
Frontier
Deal found 5/24![Frontier logo]()
$38
This Frontier deal was found by Cheapflights users on 5/24. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/12:55 pm
ONT
- DEN
Nonstop2h 22m
Frontier
Deal found 5/24![Frontier logo]()
$54
This Cheapflightsfares deal was found by Cheapflights users on 5/23. 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.
Tue 8/1110:49 am
ONT
- DEN
Nonstop2h 21m
Frontier
Deal found 5/23![Frontier logo]()
$64
This Trip.com deal was found by Cheapflights users on 5/27. 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.
Wed 6/246:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Deal found 5/27![Frontier logo]()
$81
This Southwest deal was found by Cheapflights users on 5/27. 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 6/234:05 pm
ONT
- DEN
1 stop6h 00m
Southwest
Deal found 5/27![Southwest logo]()
$83
This Cheapflightsfares deal was found by Cheapflights users on 5/27. 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 9/36:00 am
ONT
- DEN
Nonstop2h 26m
Frontier
Deal found 5/27![Frontier logo]()
$84
This Southwest deal was found by Cheapflights users on 5/28. 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 7/84:10 pm
ONT
- DEN
2 stops6h 00m
Southwest
Deal found 5/28![Southwest logo]()
$88
This United Airlines deal was found by Cheapflights users on 5/27. 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
- DEN
Nonstop2h 21m
United Airlines
Deal found 5/27![United Airlines logo]()
$89
This Cheapflightsfares deal was found by Cheapflights users on 5/27. 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 9/102:55 pm
ONT
- DEN
Nonstop2h 22m
Frontier
Deal found 5/27![Frontier logo]()
$94
This Southwest deal was found by Cheapflights users on 5/27. 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 7/16:35 pm
ONT
- COS
1 stop4h 10m
Southwest
Deal found 5/27![Southwest logo]()
$99
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 May 29, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $122 (Kiwi.com) |
One-way from | $33 (Frontier) |
Popular in | March |
Cheapest in | September |
Average price | $232 |
Good round-trip deal | $253 or less |
Good one-way deal | $139 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 May 29, 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
Wed 6/17
6:35 pm-12:05 am
1 stop4h 30m
Denver Intl
Tue 6/23
6:15 am-9:15 am
1 stop4h 00m
$165
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Wed 7/15
4:10 pm-11:10 pm
2 stops6h 00m
Denver Intl
Wed 8/12
12:25 pm-4:00 pm
1 stop4h 35m
$170
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Wed 8/12
5:05 pm-10:51 pm
1 stop4h 46m
Denver Intl
Mon 8/17
5:35 am-8:48 am
1 stop4h 13m
$197
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Tue 10/13
9:55 am-3:09 pm
1 stop4h 14m
Denver Intl
Tue 10/20
5:40 am-9:07 am
1 stop4h 27m
$197
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Mon 8/17
6:00 am-12:04 pm
1 stop5h 04m
Denver Intl
Thu 8/20
7:05 am-12:05 pm
1 stop6h 00m
$197
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Thu 8/13
5:05 pm-10:51 pm
1 stop4h 46m
Denver Intl
Thu 8/20
5:35 am-8:48 am
1 stop4h 13m
$197
OntarioColorado Springs
ONT - COS
ONTCOS
Ontario
Wed 8/19
5:00 am-1:17 pm
1 stop7h 17m
Colorado Springs
Wed 8/26
5:30 am-12:12 pm
2 stops7h 42m
$202
OntarioDenver
ONT - DEN
ONTDEN
Ontario
Tue 6/30
6:00 am-11:53 am
1 stop4h 53m
Denver Intl
Tue 7/7
5:40 am-8:47 am
1 stop4h 07m
$228
OntarioColorado Springs
ONT - COS
ONTCOS
Ontario
Wed 9/23
5:00 am-10:44 am
1 stop4h 44m
Colorado Springs
Wed 9/30
1:15 pm-10:59 pm
2 stops10h 44m
$230
OntarioColorado Springs
ONT - COS
ONTCOS
Ontario
Wed 7/15
6:35 pm-11:50 pm
1 stop4h 15m
Colorado Springs
Tue 7/21
5:10 pm-11:05 pm
2 stops6h 55m
$274
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-EGE
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-COS
ONT-EGE
ONT-DRO
What is the cheapest month to book a flight from Ontario to Colorado?
Currently, January is the cheapest month in which you can book a flight from Ontario to Colorado (average of $39). Flying from Ontario to Colorado in November is currently the most expensive (average of $85). 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 May 29, 2026.
It’s typically best to fly out from Ontario to Colorado in the evening. Doing so could potentially save you 52% 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 May 29, 2026.
The most flights from ONT to USCO are scheduled on a Monday (15 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (8 on average).
How much does it cost to fly round-trip from Ontario to Colorado?
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 57 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 May 23, 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. Monday 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 May 29, 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.
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
7.9
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
7.9
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
7.9
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
7.9
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
7.9
Food
7.0
Reviews
1 / 20
2.0
MediocreThomas,Dec 2025
SEA - DEN
Crew
8.6
Boarding
8.1
Comfort
8.0
Entertainment
7.5
Overall
7.9
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.
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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 May 29, 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 May 29, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$61 | Average$167 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$157 | Average$340 | FlexibilityNo cancel fee | On-time63% | |
| Cheapest$157 | Average$356 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$172 | Average$273 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$211 | Average$346 | FlexibilityNo cancel fee | On-time71% |