Cheap flights from Ontario, CA to United States

Travel > North America > United States

Check our current prices for flights from Ontario, CA to United States. Please note that we also give you historical search data for this city connection. These are all airfares that people found in the past, in order to find more current flight information from Ontario, CA to United States, you will need to run a search below.

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From $68 / RT details

Book your flight now with Cheapoair.com and save!

Cheap Denver airfares from $68/RT are provided by Cheapoair.com. Outbound flight is leaving on 04/01/2025, 12:59 am from Ontario Int`l (ONT) airport and arrives at Denver International Airport (DEN) at 04:16 am. The flight time is 3 hours and 17 minutes. The Returning flight departes on 04/16/2025, 10:37 pm (other return dates are also available). Date posted: 01 Feb 2025

Price evolution for flights From Ontario, CA To United States

Recent Deals on Flights from Ontario, CA to United States:Roundtrip / Oneway

• $68 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Denver, CO (DEN)	04/01/2025	12:59 am
  Denver, CO (DEN)	Ontario, CA (ONT)	04/16/2025	10:37 pm

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• $78 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Denver, CO (DEN)	03/19/2025	12:59 am
  Denver, CO (DEN)	Ontario, CA (ONT)	03/28/2025	10:37 pm

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• $86 Multiple Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	San Francisco, CA (SFO)	05/21/2025	12:59 am
  San Francisco, CA (SFO)	Ontario, CA (ONT)	06/04/2025	01:08 pm

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• $88 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Portland, OR (PDX)	04/01/2025	02:01 pm
  Portland, OR (PDX)	Ontario, CA (ONT)	04/15/2025	05:14 pm

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• $118 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Denver, CO (DEN)	04/14/2025	12:59 am
  Denver, CO (DEN)	Ontario, CA (ONT)	04/27/2025	10:38 pm

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• $24 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Denver, CO (DEN)	04/16/2025	12:59 am

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• $44 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Portland, OR (PDX)	04/02/2025	02:01 pm

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• $47 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Houston, TX (IAH)	03/31/2025	04:09 pm

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• $55 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Austin, TX (AUS)	04/01/2025	03:17 pm

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• $59 Frontier Airlines 

  From	To	Departure	Time
  Ontario, CA (ONT)	Las Vegas, NV (LAS)	05/15/2025	06:35 pm

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