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$39+ 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 6/25. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LAX
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
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 June 12, 2025.

Round-trip from

$52
(United Airlines)

One-way from

$39
(United Airlines)

Popular in

December

Cheapest in

January

Average price

$391

Good round-trip deal

$93 or less

Good one-way deal

$47 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. 4% potential increase in price ($15 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 June 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 June 12, 2025.

This United Airlines deal was found by Cheapflights users on 6/11. 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 7/156:39 pmONT - SFO
Nonstop1h 27mUnited Airlines
Tue 7/159:25 pmSFO - ONT
Nonstop1h 27mUnited Airlines
Deal found 6/11$52
This Frontier deal was found by Cheapflights users on 6/11. 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 8/137:00 amONT - LAS
Nonstop1h 11mFrontier
Wed 8/203:07 pmLAS - ONT
Nonstop1h 11mFrontier
Deal found 6/11$77
This Frontier deal was found by Cheapflights users on 6/12. 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.
Fri 8/89:41 pmONT - SFO
Nonstop1h 33mFrontier
Fri 8/1510:11 pmSFO - ONT
Nonstop1h 29mFrontier
Deal found 6/12$89
This Southwest deal was found by Cheapflights users on 6/10. 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 8/115:05 pmONT - LAS
Nonstop1h 10mSouthwest
Mon 8/119:00 pmLAS - ONT
Nonstop1h 00mSouthwest
Deal found 6/10$97
This Cheapflightsfares deal was found by Cheapflights users on 6/12. 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 8/712:59 amONT - DEN
Nonstop2h 20mFrontier
Mon 8/1110:29 pmDEN - ONT
Nonstop2h 21mFrontier
Deal found 6/12$119
This Cheapflightsfares deal was found by Cheapflights users on 6/10. 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 8/610:03 amONT - SEA
Nonstop2h 50mFrontier
Sat 8/161:42 pmSEA - ONT
Nonstop2h 54mFrontier
Deal found 6/10$126
This CheapOair deal was found by Cheapflights users on 6/12. 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.
Sat 8/168:09 pmONT - DFW
Nonstop3h 15mFrontier
Sat 8/239:45 amDFW - ONT
Nonstop3h 04mFrontier
Deal found 6/12$149
This United Airlines deal was found by Cheapflights users on 6/11. 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 8/205:10 amONT - DEN
Nonstop2h 17mUnited Airlines
Tue 8/267:25 pmDEN - ONT
Nonstop2h 18mUnited Airlines
Deal found 6/11$157
This Southwest deal was found by Cheapflights users on 6/11. 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 8/206:05 amONT - DEN
2 stops7h 00mSouthwest
Mon 8/258:30 amDEN - ONT
Nonstop2h 15mSouthwest
Deal found 6/11$172
This Alaska Airlines deal was found by Cheapflights users on 6/10. 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 Alaska Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/136:00 amONT - SEA
Nonstop2h 45mAlaska Airlines
Sat 9/207:55 amSEA - ONT
Nonstop2h 49mAlaska Airlines
Deal found 6/10$177
This American Airlines deal was found by Cheapflights users on 6/11. 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 6/204:50 pmONT - SFO
1 stop5h 41mAmerican Airlines
Tue 6/249:15 amSFO - ONT
1 stop6h 58mAmerican Airlines
Deal found 6/11$187
This Hawaiian Airlines deal was found by Cheapflights users on 6/9. 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 Hawaiian Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 8/66:10 pmONT - DFW
1 stop8h 30mHawaiian Airlines
Wed 8/134:46 pmDFW - ONT
1 stop9h 13mHawaiian Airlines
Deal found 6/9$202

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 June 12, 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

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 7/15

6:39 pm-8:06 pm

Nonstop1h 27m

San Francisco

Tue 7/15

9:25 pm-10:52 pm

Nonstop1h 27m

$52

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Wed 8/13

7:00 am-8:11 am

Nonstop1h 11m

Las Vegas Harry Reid Intl

Tue 8/19

3:07 pm-4:18 pm

Nonstop1h 11m

$77

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 8/8

9:41 pm-11:14 pm

Nonstop1h 33m

San Francisco

Fri 8/15

10:11 pm-11:40 pm

Nonstop1h 29m

$89

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Mon 8/11

5:05 pm-6:15 pm

Nonstop1h 10m

Las Vegas Harry Reid Intl

Mon 8/11

9:00 pm-10:00 pm

Nonstop1h 00m

$97

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Sat 8/9

12:59 am-4:19 am

Nonstop2h 20m

Denver Intl

Mon 8/11

7:53 am-9:13 am

Nonstop2h 20m

$119

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Wed 8/6

10:03 am-12:53 pm

Nonstop2h 50m

Seattle/Tacoma Intl

Sat 8/16

1:42 pm-4:36 pm

Nonstop2h 54m

$126

OntarioDallas

ONT - DFW

ONTDFW

Ontario

Tue 8/5

10:06 am-3:19 pm

Nonstop3h 13m

Dallas/Fort Worth

Sat 8/16

6:09 pm-7:14 pm

Nonstop3h 05m

$148

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 8/20

5:10 am-8:27 am

Nonstop2h 17m

Denver Intl

Tue 8/26

7:25 pm-8:43 pm

Nonstop2h 18m

$157

OntarioDenver

ONT - DEN

ONTDEN

Ontario

Wed 8/20

2:45 pm-6:00 pm

Nonstop2h 15m

Denver Intl

Tue 8/26

10:45 am-5:35 pm

2 stops7h 50m

$172

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 9/13

6:00 am-8:45 am

Nonstop2h 45m

Seattle/Tacoma Intl

Sat 9/20

7:55 am-10:44 am

Nonstop2h 49m

$177

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/10

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 $327). 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 June 12, 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.

Rainfall in USA by month

Plan your trip to USA by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in USA ranges from 2.8 - 4.5 inches per month. July is typically the wettest month, when rainfall can reach 4.5 in. February is typically the driest time to visit USA when rainfall is around 2.8 in.

Temperature in USA by month

Plan your trip to USA by taking into account the average temperature totals by month.

If weather is an important factor for your trip to USA, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 77.0 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 33.8 F).

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 June 12, 2025.
Peruse reviews from past customers who have flown with Alaska Airlines, Southwest and Delta from Ontario to USA to help guide your decision. Reviews also offer insight into each airline's entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Comfort

7.8

Food

7.1

Overall

8.0

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Comfort

7.8

Food

7.1

Overall

8.0

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,287 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Comfort

7.8

Food

7.1

Overall

8.0

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,950 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Comfort

7.8

Food

7.1

Overall

8.0

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Hawaiian Airlines
7.9
Good
2,494 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Comfort

7.8

Food

7.1

Overall

8.0

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,790 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Boarding

8.1

Comfort

7.8

Food

7.1

Overall

8.0

Entertainment

7.1

Crew

8.5

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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.

  • What are the cheapest airlines to fly from Ontario to USA one-way?

    $39 is the cheapest one-way deal found within the past few days, from United Airlines. You may also be able to find cheap deals on Southwest and Frontier, with prices starting from $49 and $51, respectively.

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

    While some choose either Ontario - New York John F Kennedy Intl or Ontario - Chicago O'Hare Intl, 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 $327). 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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Top 9 airlines flying from Ontario to USA

Discover the top 9 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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$22Average$155FlexibilityNo cancel feeOn-time65%
FrontierCheapest$34Average$172FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$58Average$388FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$67Average$296FlexibilityNo cancel feeOn-time75%
DeltaCheapest$85Average$351FlexibilityNo cancel feeOn-timeN/A
Hawaiian AirlinesCheapest$96Average$257FlexibilityNo cancel feeOn-time85%
SouthwestCheapest$99Average$367FlexibilityNo cancel feeOn-time63%
American AirlinesCheapest$236Average$417FlexibilityNo cancel feeOn-time71%
JetBlueCheapest$247Average$361FlexibilityNo cancel feeOn-time62%

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