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$29+ Cheap flights from Ontario (ONT) to the United States

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 12/14. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LAX
Oct 17 — Oct 241
Fri 10/17
Fri 10/24
1 adult, Economy
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Cheap flight deals from Ontario to USA

Keep the following information in mind while searching for Ontario to USA flight deals. Data was last updated September 17, 2025.

Round-trip from

$58
(Cheapflightsfares)

One-way from

$29
(Southwest)

Popular in

December

Cheapest in

January

Average price

$312

Good round-trip deal

$99 or less

Good one-way deal

$69 or less
From Ontario to USA
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One-way flight from Ontario to USA
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Highest demand for flights based on searches. 6% potential increase in price ($24 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($8 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Price to beat on a round-trip flight from Ontario to USA.
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Price to beat on a one-way flight from Ontario to USA.
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Find flight deals from Ontario to USA

Cheapest flights from Ontario to USA
Explore the most affordable flight options available from Ontario to USA. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 17, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 9/16. 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.
Fri 10/37:30 pmONT - LAS
Nonstop1h 12mFrontier
Sat 10/48:49 pmLAS - ONT
Nonstop1h 07mFrontier
Deal found 9/16$58
This Cheapflightsfares deal was found by Cheapflights users on 9/14. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/26:00 amONT - LAS
Nonstop1h 11mFrontier
Tue 10/77:33 pmLAS - ONT
Nonstop1h 09mFrontier
Deal found 9/14$62
This Cheapflightsfares deal was found by Cheapflights users on 9/15. 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.
Sat 9/278:00 amONT - LAS
Nonstop1h 11mFrontier
Wed 10/297:33 pmLAS - ONT
Nonstop1h 09mFrontier
Deal found 9/15$65
This Frontier deal was found by Cheapflights users on 9/15. 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.
Thu 9/256:00 amONT - LAS
Nonstop1h 11mFrontier
Mon 10/67:45 pmLAS - ONT
Nonstop1h 11mFrontier
Deal found 9/15$66
This Cheapflightsfares deal was found by Cheapflights users on 9/15. 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.
Sat 10/117:04 amONT - DEN
Nonstop2h 27mFrontier
Tue 10/1410:29 pmDEN - ONT
Nonstop2h 21mFrontier
Deal found 9/15$67
This Cheapflightsfares deal was found by Cheapflights users on 9/16. 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 10/96:05 amONT - LAS
Nonstop1h 11mFrontier
Sat 10/117:33 pmLAS - ONT
Nonstop1h 09mFrontier
Deal found 9/16$68
This Frontier deal was found by Cheapflights users on 9/15. 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 10/147:04 amONT - DEN
Nonstop2h 27mFrontier
Sat 10/1810:29 pmDEN - ONT
Nonstop2h 21mFrontier
Deal found 9/15$68
This Booking.com deal was found by Cheapflights users on 9/15. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/147:04 amONT - DEN
Nonstop2h 27mFrontier
Fri 10/178:15 amDEN - ONT
Nonstop2h 20mFrontier
Deal found 9/15$71
This Cheapflightsfares deal was found by Cheapflights users on 9/14. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/256:00 amONT - LAS
Nonstop1h 11mFrontier
Thu 9/2510:22 amLAS - ONT
Nonstop1h 16mFrontier
Deal found 9/14$72
This Cheapflightsfares deal was found by Cheapflights users on 9/15. 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 10/29:46 pmONT - SFO
Nonstop1h 29mFrontier
Fri 10/310:11 pmSFO - ONT
Nonstop1h 27mFrontier
Deal found 9/15$72
This Frontier deal was found by Cheapflights users on 9/14. 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.
Mon 9/296:00 amONT - LAS
Nonstop1h 11mFrontier
Fri 10/36:10 amLAS - ONT
Nonstop1h 07mFrontier
Deal found 9/14$73
This Frontier deal was found by Cheapflights users on 9/15. 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.
Wed 10/156:53 amONT - DEN
Nonstop2h 25mFrontier
Wed 10/1510:29 pmDEN - ONT
Nonstop2h 21mFrontier
Deal found 9/15$73

Cheapflights Fare Finder

 
Customize your flight search to find flights from Ontario to USA 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 September 17, 2025.
Use the filters below to find and compare flights from Ontario to the United States that are best for you.

Fly from

Ontario

Fly to

USA

Route

Depart

Return

Price

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Sat 10/11

8:45 pm-9:50 pm

Nonstop1h 05m

Las Vegas Harry Reid Intl

Tue 10/14

7:20 am-8:25 am

Nonstop1h 05m

$77

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Sun 10/26

9:05 pm-10:10 pm

Nonstop1h 05m

Las Vegas Harry Reid Intl

Tue 10/28

7:20 am-8:25 am

Nonstop1h 05m

$77

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Thu 12/4

8:55 pm-9:55 pm

Nonstop1h 00m

Las Vegas Harry Reid Intl

Sat 12/6

5:55 am-11:10 am

1 stop5h 15m

$87

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Tue 11/18

8:55 pm-9:55 pm

Nonstop1h 00m

Las Vegas Harry Reid Intl

Thu 11/20

2:15 pm-3:20 pm

Nonstop1h 05m

$87

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Thu 11/13

9:15 pm-10:15 pm

Nonstop1h 00m

Las Vegas Harry Reid Intl

Sat 11/15

2:20 pm-3:25 pm

Nonstop1h 05m

$87

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Wed 10/15

9:10 pm-10:15 pm

Nonstop1h 05m

Las Vegas Harry Reid Intl

Wed 10/22

8:20 pm-9:25 pm

Nonstop1h 05m

$87

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Mon 11/10

9:15 pm-10:15 pm

Nonstop1h 00m

Las Vegas Harry Reid Intl

Wed 11/12

8:35 am-9:35 am

Nonstop1h 00m

$87

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Fri 11/7

9:15 pm-10:15 pm

Nonstop1h 00m

Las Vegas Harry Reid Intl

Sat 11/8

8:40 am-9:40 am

Nonstop1h 00m

$87

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Tue 12/2

8:55 pm-9:55 pm

Nonstop1h 00m

Las Vegas Harry Reid Intl

Thu 12/4

5:10 pm-6:15 pm

Nonstop1h 05m

$97

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 10/18

7:35 am-10:35 am

Nonstop3h 00m

Seattle/Tacoma Intl

Fri 10/24

7:55 pm-10:41 pm

Nonstop2h 46m

$133

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/14

Showing 1-10 of 60 results
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Best time to book a flight from Ontario to USA

Have a flexible travel schedule? Discover the best time to fly to USA from Ontario with our price prediction graph.
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 the United States

What is the cheapest month to book a flight from Ontario to USA?

Currently, January is the cheapest month in which you can book a flight from Ontario to USA (average of $246). Flying from Ontario to USA in March is currently the most expensive (average of $325). 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 US?

Find hourly flight availability from Ontario to USA. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 17, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Ontario to USA as you normally would.

Reviews of airlines servicing USA

Get insights into the airlines that provide service to USA. 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 USA. Reviews last updated September 17, 2025.
Read reviews from past customers who have flown Southwest, Delta, and United Airlines from Ontario to the United States. 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.
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Crew

8.6

Boarding

8.1

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,242 reviews
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Crew

8.6

Boarding

8.1

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Delta
8.0
Very good
7,961 reviews
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Crew

8.6

Boarding

8.1

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
8,926 reviews
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Crew

8.6

Boarding

8.1

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Crew

8.6

Boarding

8.1

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Frontier
5.8
Fair
3,173 reviews
Southwest
8.0
Very good
4,242 reviews

Entertainment

7.5

Comfort

8.0

Overall

8.0

Crew

8.6

Boarding

8.1

Food

7.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from Ontario to USA. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly from for flights from Ontario to United States?

    Ontario (ONT) is the airport you will fly out of if you book a flight from Ontario to United States. It is only a 3.1 mi journey to Ontario (ONT) from Ontario’s city center.

  • How long is the flight from Ontario to USA?

    Departing from Ontario to USA will take you 1h 05m. The distance from Ontario to USA is about 197 mi. Generally, flights for this route are nonstop.

  • What are the most popular routes from Ontario to USA?

    While some choose either Ontario - New York John F Kennedy Intl or Ontario - San Francisco, Ontario - Seattle/Tacoma Intl is the most popular route from Ontario to USA.

  • Can I find deals for flights from Ontario to USA that include hotel bookings?

    Yes. In addition to deals on Ontario to USA flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Ontario to USA?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to USA.

  • Can I find deals for business class flights from Ontario to USA?

    Yes. Cheapflights offers flight deals from Ontario to USA by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Ontario to USA?

    Currently, January is the cheapest month in which you can book a flight from Ontario to USA (average of $246). Flying from Ontario to USA in March is currently the most expensive (average of $325). 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.

See more FAQs

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Alternative routes for Ontario to USA

See prices for flight routes from nearby airports that may be better suited for you.
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San Francisco to John F Kennedy Intl flights
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Top 8 airlines flying from Ontario to USA

Discover the top 8 airlines that operate flights from Ontario to USA. 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 September 17, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$22Average$142FlexibilityNo cancel feeOn-time65%
FrontierCheapest$36Average$188FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$58Average$392FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$67Average$375FlexibilityNo cancel feeOn-time75%
DeltaCheapest$97Average$362FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$97Average$379FlexibilityNo cancel feeOn-time63%
JetBlueCheapest$223Average$330FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$237Average$428FlexibilityNo cancel feeOn-time71%

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