Cheap Flights from Ontario, CA to Denver, CO from $39

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On Cheapflightsplus.com you will find 8 direct and 112 connecting flights from Ontario to Denver. You can compare airfare deals from 4 airlines and multiple travel sites from $39, book and save on cheap plane tickets and last minute offers. Also check out ONT-DEN flight schedule to find best flight time, convenient departure and arrival airports.

Find One-Way and Round-Trip Ontario to Denver Flight Deals

To find the cheapest one way airline ticket select the date with the lowest price on the calendar below and click «Find Flights». To search for round-trip flight deals click on the link «Check prices for return flights» and select the date of the return flight. Cheapest flights in November: $39 (one-way), $67 (round-trip).

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Best Flights from Ontario to Denver Today

Take a look at the list of non stop flights and flights with layovers from Ontario to Denver with the lowest price of $39. The fastest direct flight takes 2h 16m and the fastest connecting – 4h 30m.

Price	Departure	Arrival	Flight Duration	Airline	Flight
from $39 Find flight	00:59 Ontario Ontario Int.	04:17 Denver Denver International	2h 18m	Frontier Airlines	F91500
from $111 Find flight	13:15 Ontario Ontario Int.	16:31 Denver Denver International	2h 16m	United Airlines	UA1417
from $111 Find flight	05:10 Ontario Ontario Int.	08:27 Denver Denver International	2h 17m	United Airlines	UA2446
from $111 Find flight	18:38 Ontario Ontario Int.	21:55 Denver Denver International	2h 17m	United Airlines	UA368
from $113 Find flight	05:10 Ontario Ontario Int.	08:27 Denver Denver International	2h 17m	United Airlines	UA1479
from $113 Find flight	13:15 Ontario Ontario Int.	16:32 Denver Denver International	2h 17m	United Airlines	UA1697
from $119 Find flight	05:05 Ontario Ontario Int.	08:23 Denver Denver International	2h 18m	United Airlines	UA1575
from $144 Find flight	18:28 Ontario Ontario Int.	21:47 Denver Denver International	2h 19m	United Airlines	UA635
from $73 Find flight	17:15 Ontario Ontario Int.	22:45 Denver Denver International	4h 30m layover 1h 12m - Las Vegas	Frontier Airlines	F91358 F94612
from $96 Find flight	08:00 Ontario Ontario Int.	03:59+1 день Denver Denver International	18h 59m layover 15h 47m - Las Vegas	Frontier Airlines	F92232 F91994
from $117 Find flight	21:41 Ontario Ontario Int.	18:43+1 день Denver Denver International	20h 2m layover 15h 47m - San Francisco	Frontier Airlines	F92677 F91094
from $119 Find flight	13:31 Ontario Ontario Int.	21:46 Denver Denver International	7h 15m layover 1h 45m - Seattle	Hawaiian Airlines	HA6289 HA6654
from $120 Find flight	16:00 Ontario Ontario Int.	23:59 Denver Denver International	6h 59m layover 1h 37m - Seattle	Hawaiian Airlines	HA6290 HA6652
from $120 Find flight	14:21 Ontario Ontario Int.	23:59 Denver Denver International	8h 38m layover 3h 19m - Seattle	Hawaiian Airlines	HA6307 HA6652
from $127 Find flight	15:54 Ontario Ontario Int.	07:36+1 день Denver Denver International	14h 42m layover 8h 42m - Houston	Frontier Airlines	F93132 F93229
from $128 Find flight	06:00 Ontario Ontario Int.	14:06 Denver Denver International	7h 6m layover 1h 31m - Seattle	Alaska Airlines	AS1091 AS535

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*Departure and arrival times - local. Prices indicated for one-way flights. Information updated on July 13, 2025

Flight Schedule Ontario (California) to Denver (Colorado)

Full flight schedule will help you in detecting at what time planes fly from Ontario to Denver. You can also specify the concrete flights and airlines on the route and how long the flight actually is. Use the calendar for today, tomorrow or other specific date as some flights are available only on certain days of the week.

Departure	Flight Details	Flight Duration	Price
00:59 — 04:17	00:59 — 04:17 F91500 Frontier Airlines Ontario — Denver	2h 18m	Find flight from$39
05:05 — 08:23	05:05 — 08:23 UA1575 United Airlines Ontario — Denver	2h 18m	Find flight from$119
05:10 — 08:27	05:10 — 08:27 UA2446 United Airlines Ontario — Denver	2h 17m	Find flight from$111
05:10 — 08:27	05:10 — 08:27 UA1479 United Airlines Ontario — Denver	2h 17m	Find flight from$113
13:15 — 16:31	13:15 — 16:31 UA1417 United Airlines Ontario — Denver	2h 16m	Find flight from$111
13:15 — 16:32	13:15 — 16:32 UA1697 United Airlines Ontario — Denver	2h 17m	Find flight from$113
18:28 — 21:47	18:28 — 21:47 UA635 United Airlines Ontario — Denver	2h 19m	Find flight from$144
18:38 — 21:55	18:38 — 21:55 UA368 United Airlines Ontario — Denver	2h 17m	Find flight from$111
06:00 — 14:06	06:00 — 08:42 AS1091 Alaska Airlines Ontario — Seattle 1h 31m stop 10:20 — 14:07 AS535 Alaska Airlines Seattle — Denver	7h 6m including layover	Find flight from$128
06:00 — 21:46	06:00 — 08:45 HA6288 Hawaiian Airlines Ontario — Seattle 9h 14m stop 18:00 — 21:47 HA6654 Hawaiian Airlines Seattle — Denver	14h 46m including layover	Find flight from$171
08:00 — 03:59 +1 day	06:00 — 07:16 F92232 Frontier Airlines Ontario — Las Vegas 15h 47m stop 00:59 — 04:00 F91994 Frontier Airlines Las Vegas — Denver	18h 59m including layover	Find flight from$96
08:00 — 20:00	15:56 — 17:09 F92232 Frontier Airlines Ontario — Las Vegas 7h 39m stop 06:25 — 09:29 F93540 Frontier Airlines Las Vegas — Denver	11h including layover	Find flight from$99
09:35 — 18:14	09:35 — 10:54 UA1585 United Airlines Ontario — San Francisco 3h 40m stop 14:34 — 18:14 UA1596 United Airlines San Francisco — Denver	7h 39m including layover	Find flight from$198
09:36 — 16:35	09:35 — 10:54 UA1585 United Airlines Ontario — San Francisco 2h stop 12:55 — 16:36 UA1333 United Airlines San Francisco — Denver	5h 59m including layover	Find flight from$185
11:15 — 18:02	10:00 — 12:22 HA6284 Hawaiian Airlines Ontario — Portland 59m stop 14:30 — 18:09 HA6338 Hawaiian Airlines Portland — Denver	5h 47m including layover	Find flight from$216
11:15 — 18:02	10:03 — 12:19 AS2456 Alaska Airlines Ontario — Portland 59m stop 14:34 — 18:10 AS1235 Alaska Airlines Portland — Denver	5h 47m including layover	Find flight from$224
12:00 — 23:59	12:00 — 14:38 AS1111 Alaska Airlines Ontario — Seattle 5h 39m stop 20:17 — 23:59 AS642 Alaska Airlines Seattle — Denver	10h 59m including layover	Find flight from$225
13:37 — 20:00	17:15 — 18:28 F91358 Frontier Airlines Ontario — Las Vegas 1h 56m stop 15:46 — 18:57 F93540 Frontier Airlines Las Vegas — Denver	5h 23m including layover	Find flight from$93
14:21 — 23:59	14:21 — 16:58 HA6307 Hawaiian Airlines Ontario — Seattle 3h 19m stop 20:17 — 23:59 HA6652 Hawaiian Airlines Seattle — Denver	8h 38m including layover	Find flight from$120
14:21 — 23:59	14:21 — 16:58 AS1242 Alaska Airlines Ontario — Seattle 3h 19m stop 20:17 — 23:59 AS642 Alaska Airlines Seattle — Denver	8h 38m including layover	Find flight from$130
15:54 — 07:36 +1 day	12:40 — 18:11 F93132 Frontier Airlines Ontario — Houston 8h 42m stop 06:00 — 07:50 F93229 Frontier Airlines Houston — Denver	14h 42m including layover	Find flight from$127
16:00 — 23:59	16:00 — 18:40 HA6290 Hawaiian Airlines Ontario — Seattle 1h 37m stop 20:17 — 23:59 HA6652 Hawaiian Airlines Seattle — Denver	6h 59m including layover	Find flight from$120
16:00 — 23:59	16:00 — 18:40 AS1119 Alaska Airlines Ontario — Seattle 1h 37m stop 20:17 — 23:59 AS642 Alaska Airlines Seattle — Denver	6h 59m including layover	Find flight from$130
17:15 — 22:45	13:17 — 14:29 F91358 Frontier Airlines Ontario — Las Vegas 1h 12m stop 20:33 — 23:36 F94612 Frontier Airlines Las Vegas — Denver	4h 30m including layover	Find flight from$73
17:26 — 04:00 +1 day	09:26 — 10:33 F91358 Frontier Airlines Ontario — Las Vegas 6h 20m stop 06:30 — 09:38 F91994 Frontier Airlines Las Vegas — Denver	9h 34m including layover	Find flight from$73
19:25 — 11:55 +1 day	19:25 — 22:05 HA6287 Hawaiian Airlines Ontario — Seattle 9h 57m stop 08:02 — 11:55 HA6555 Hawaiian Airlines Seattle — Denver	15h 30m including layover	Find flight from$171
19:25 — 11:55 +1 day	19:25 — 22:05 AS1399 Alaska Airlines Ontario — Seattle 9h 57m stop 08:02 — 11:55 AS682 Alaska Airlines Seattle — Denver	15h 30m including layover	Find flight from$180
21:41 — 18:43 +1 day	21:41 — 23:13 F92677 Frontier Airlines Ontario — San Francisco 15h 47m stop 15:00 — 18:43 F91094 Frontier Airlines San Francisco — Denver	20h 2m including layover	Find flight from$117
21:41 — 09:44 +1 day	06:00 — 07:35 F92677 Frontier Airlines Ontario — San Francisco 6h 47m stop 06:55 — 10:30 F91230 Frontier Airlines San Francisco — Denver	11h 3m including layover	Find flight from$128
07:10 — 21:59	07:10 — 09:27 AS1058 Alaska Airlines Ontario — Portland 3h 57m stop 13:24 — 14:26 AS1016 Alaska Airlines Portland — Seattle 3h 46m stop 18:12 — 21:59 AS1163 Alaska Airlines Seattle — Denver	13h 49m including layover	Find flight from$180
07:10 — 21:59	07:10 — 09:27 AS1058 Alaska Airlines Ontario — Portland 5h 3m stop 14:30 — 15:33 AS3380 Alaska Airlines Portland — Seattle 2h 39m stop 18:12 — 21:59 AS1163 Alaska Airlines Seattle — Denver	13h 49m including layover	Find flight from$186
10:03 — 23:59	10:03 — 12:19 AS2456 Alaska Airlines Ontario — Portland 3h 21m stop 15:40 — 16:40 AS3446 Alaska Airlines Portland — Seattle 3h 37m stop 20:17 — 23:59 AS642 Alaska Airlines Seattle — Denver	12h 56m including layover	Find flight from$182
10:03 — 23:59	10:03 — 12:19 AS2456 Alaska Airlines Ontario — Portland 1h 1m stop 13:20 — 14:20 AS1016 Alaska Airlines Portland — Seattle 5h 57m stop 20:17 — 23:59 AS642 Alaska Airlines Seattle — Denver	12h 56m including layover	Find flight from$188

Departure	Arrival	Flight Details	Flight Time	Price
		stop stop	including layover	Find flight from$

*Departure and arrival times - local. Updated on July 13, 2025

Flight Information

Below we will explain in detail what the flights cost on the destination from Ontario to Denver depends on and how to choose the most interesting flight option for you.

Distance between Ontario and Denver is 1316 miles. Time difference between the cities is 1h. Airplanes depart 00:59 to 21:41 from 2 Ontario airports and arrive 00:59 to 21:41 to 2 Denver airports. Average flight time is 2h 17m.

The fastest flight 2h 16m
Average flight time 2h 17m
The earliest flight 00:59
The latest flight 21:41
Distance 818 ml

The cheapest months to travel to Denver are november (from 39 $), july (from 39 $), january (from 52 $).

The most expensive months are june (from 110 $), october (from 100 $), august (from 96 $).

What is the lowest airfare Ontario to Denver?

The cheapest plane ticket found by our users is $39. This airfare is for economy class on one-way F91500 flight by Frontier Airlines for July 15, 2025 which leaves Ontario Int. in Ontario at 00:59 am and arrives at Denver Denver International at 04:17.

Economy class

$39

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Business class

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First class

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Popular Airlines on the Route

The flight Ontario — Denver is served by 4 regular airlines and 1 low-cost airline. Most of the flights on this route are operated by Alaska Airlines - 43 departures per week at the price of from $ 128 . And the most expensive tickets are offered by Hawaiian Airlines airline - from $ 620.

Direct flights

There are 8 nonstop flights on the route. The fastest direct flight is UA1417 by United Airlines takes 2h 16m and the cheapest is F91500 by Frontier Airlines for $39.

F9 - Frontier Airlines

from $39

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UA - United Airlines

from $111

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Connecting Flights

There are 112 flights with layovers on the route. The fastest connecting flight is F91358 by Frontier Airlines takes 4h 30m and the cheapest is F91500 by Frontier Airlines for $73.

AS - Alaska Airlines

from $128

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F9 - Frontier Airlines

from $73

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HA - Hawaiian Airlines

from $119

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UA - United Airlines

from $185

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Airports

You can fly from Ontario to Denver from 2 airports (Ontario Int., International Heliport).

Ontario airports

Ontario Int.-ONT

from $39
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International Heliport-JIO

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Denver airports

Denver International-DEN

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Arapahoe Co-APA

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Airplanes

There are flights to Denver from Ontario by 4 airlines that use 0 aircraft brands. They range from huge modern airplanes to small-sized.

Top Domestic Destinations from Ontario

You may also consider searching for discounted plane tickets to some other popular places from Ontario within United States.

Ontario — Phoenix

from $56

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Ontario — Denver

from $65

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Ontario — Austin

from $67

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Ontario — Miami

from $62

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Ontario — Tucson

from $80

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Ontario — Las Vegas

from $63

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Ontario — Seattle

from $65

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Ontario — Boise

from $70

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Ontario — Chicago

from $78

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Ontario — Philadelphia

from $62

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Top International Destinations from Ontario

Our state-of-the art metasearch will definitely provide you with the best airfare on international flights. We’re proud to partner with many reliable travel suppliers located outside the US what gives us an opportunity to offer the most competitive prices on far destinations.

Ontario — London

from $62

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Ontario — San Jose

from $61

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Ontario — Guadalajara

from $70

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Ontario — Cancun

from $74

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How to book a plane ticket yourself?

Fill in the search parameters — cities of departure and destination, departure and return dates and click «Find flights»
Select the best flight that you like. Please, check the airports of departure and arrival. Select the best fare, but pay attention to the following flight details - airports of departure and arrival, flight duration and layovers. Please use filters and sort to find the best flight.
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That's it — you will receive an email with your e-ticket usually within 10 minutes after your flight is confirmed. Please, print the e-ticket and have it with you at the airport. You would need to have only a passport and/or a required form of ID to travel. Please, check your Visa requirements if you travel outside of the United States or Canada.
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