Cheap Flights from Ontario, CA to Denver, CO from $29

On Cheapflightsplus.com you will find 9 direct and 123 connecting flights from Ontario to Denver. You can compare airfare deals from 4 airlines and multiple travel sites from $29, 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: $29 (one-way), $50 (round-trip).
Direct flights
  • Check to choose departure date Check to choose departure date
Check prices for return flight
Find flights
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 Arrival Flight Details Flight Duration Price
00:59 — 04:17
00:59 — 04:17 F91500 Frontier Airlines
Ontario — Denver
2h 18m
Find flight
from$29
05:05 — 08:23
05:05 — 08:23 UA1575 United Airlines
Ontario — Denver
2h 18m
Find flight
from$89
05:10 — 08:27
05:10 — 08:27 UA2446 United Airlines
Ontario — Denver
2h 17m
Find flight
from$83
05:10 — 08:27
05:10 — 08:27 UA1479 United Airlines
Ontario — Denver
2h 17m
Find flight
from$84
13:15 — 16:31
13:15 — 16:31 UA1417 United Airlines
Ontario — Denver
2h 16m
Find flight
from$83
13:15 — 16:32
13:15 — 16:32 UA1697 United Airlines
Ontario — Denver
2h 17m
Find flight
from$84
17:21 — 20:42
17:21 — 20:42 F92908 Frontier Airlines
Ontario — Denver
2h 21m
Find flight
from$62
18:28 — 21:47
18:28 — 21:47 UA635 United Airlines
Ontario — Denver
2h 19m
Find flight
from$108
18:38 — 21:55
18:38 — 21:55 UA368 United Airlines
Ontario — Denver
2h 17m
Find flight
from$83
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$96
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$128
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$72
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$74
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$148
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$138
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$162
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$168
12:00 — 19:32
12:00 — 14:38 HA6289 Hawaiian Airlines
Ontario — Seattle
1h 11m stop
15:49 — 19:32 HA6650 Hawaiian Airlines
Seattle — Denver
6h 32m
including layover
Find flight
from$163
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$69
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$90
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$97
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$95
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$90
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$97
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$54
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$54
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$128
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$135
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$87
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$96
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$135
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$139
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$136
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$141
*Departure and arrival times - local. Updated on July 3, 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 october (from 100 $), august (from 96 $), september (from 93 $).

What is the lowest airfare Ontario to Denver?

The cheapest plane ticket found by our users is $29. This airfare is for economy class on one-way F91500 flight by Frontier Airlines for July 8, 2025 which leaves Ontario Int. in Ontario at 00:59 am and arrives at Denver Denver International at 04:17.

Economy class
$29
Find
Business class
?
Find
First class
?
Find

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 - 47 departures per week at the price of from $ 96 . And the most expensive tickets are offered by Hawaiian Airlines airline - from $ 465.

Direct flights

There are 9 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 $29.

  • F9 - Frontier Airlines
    from $29
    Find
  • UA - United Airlines
    from $83
    Find
See more direct flights

Connecting Flights

There are 123 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 $54.

  • AS - Alaska Airlines
    from $96
    Find
  • F9 - Frontier Airlines
    from $54
    Find
  • HA - Hawaiian Airlines
    from $89
    Find
  • UA - United Airlines
    from $138
    Find
See more connecting flights

Airports

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

Ontario airports

  • Ontario Int.-ONT
    from $29
    Find
  • International Heliport-JIO
    Find

Denver airports

  • Denver International-DEN
    Find
  • Arapahoe Co-APA
    Find

How to book a plane ticket yourself?

How to book an air 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.
  • Click «Buy» when you are ready — our system will redirect you to the site that sells the selected flight ticket.
  • Fill in all passenger and payment information — passport and contact information, please double check all passengers’ names and make a payment for your itinerary.
  • 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.

    To find a plane ticket, please select dates.

Back