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$30+ 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 8/4. Fares are subject to change and may not be available on all flights or dates of travel.
ONT — LAX
Aug 3 — Aug 101
Sun 8/3
Sun 8/10
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 July 29, 2025.

Round-trip from

$63
(Frontier)

One-way from

$30
(CheapOair)

Popular in

December

Cheapest in

January

Average price

$358

Good round-trip deal

$88 or less

Good one-way deal

$72 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. 5% potential increase in price ($21 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 July 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 July 29, 2025.

This Mytrip deal was found by Cheapflights users on 7/29. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/35:14 pmONT - LAS
Nonstop1h 14mFrontier
Mon 8/47:45 pmLAS - ONT
Nonstop1h 07mFrontier
Deal found 7/29$63
This Cheapflightsfares deal was found by Cheapflights users on 7/27. 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 8/159:41 pmONT - SFO
Nonstop1h 33mFrontier
Sun 8/1710:11 pmSFO - ONT
Nonstop1h 29mFrontier
Deal found 7/27$74
This United Airlines deal was found by Cheapflights users on 7/29. 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 8/196:00 amONT - SFO
Nonstop1h 19mUnited Airlines
Tue 8/194:17 pmSFO - ONT
Nonstop1h 20mUnited Airlines
Deal found 7/29$97
This Southwest deal was found by Cheapflights users on 7/28. 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 8/2710:20 amONT - LAS
Nonstop1h 05mSouthwest
Wed 9/38:30 amLAS - ONT
1 stop4h 40mSouthwest
Deal found 7/28$107
This Cheapflightsfares deal was found by Cheapflights users on 7/29. 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.
Mon 8/258:25 amONT - PDX
Nonstop2h 24mFrontier
Fri 8/297:04 pmPDX - ONT
Nonstop2h 23mFrontier
Deal found 7/29$110
This Cheapflightsfares deal was found by Cheapflights users on 7/28. 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.
Mon 8/1110:03 amONT - SEA
Nonstop2h 50mFrontier
Thu 8/141:42 pmSEA - ONT
Nonstop2h 54mFrontier
Deal found 7/28$144
This Alaska Airlines deal was found by Cheapflights users on 7/29. 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 10/1111:15 amONT - PDX
Nonstop2h 19mAlaska Airlines
Wed 10/159:30 pmPDX - ONT
Nonstop2h 21mAlaska Airlines
Deal found 7/29$157
This American Airlines deal was found by Cheapflights users on 7/29. 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.
Sat 10/41:10 pmONT - PDX
1 stop6h 13mAmerican Airlines
Sat 10/185:05 amPDX - ONT
1 stop6h 56mAmerican Airlines
Deal found 7/29$159
This Hawaiian Airlines deal was found by Cheapflights users on 7/29. 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.
Sat 8/236:00 amONT - SEA
Nonstop2h 45mHawaiian Airlines
Tue 8/265:20 amSEA - ONT
1 stop4h 06mHawaiian Airlines
Deal found 7/29$167
This Delta deal was found by Cheapflights users on 7/28. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 9/611:40 amONT - SEA
Nonstop2h 45mDelta
Sat 9/138:15 amSEA - ONT
Nonstop2h 54mDelta
Deal found 7/28$177
This Southwest deal was found by Cheapflights users on 7/29. 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.
Fri 9/266:20 amONT - HOU
Nonstop3h 10mSouthwest
Thu 10/21:40 pmHOU - ONT
Nonstop3h 15mSouthwest
Deal found 7/29$191
This American Airlines deal was found by Cheapflights users on 7/28. 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.
Thu 9/410:53 amONT - HOU
1 stop5h 17mAmerican Airlines
Sun 9/76:00 amHOU - ONT
1 stop6h 05mAmerican Airlines
Deal found 7/28$209

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 July 29, 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

Mon 8/4

6:00 am-7:13 am

Nonstop1h 13m

Las Vegas Harry Reid Intl

Tue 8/5

3:09 pm-4:20 pm

Nonstop1h 11m

$63

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 8/15

9:41 pm-11:14 pm

Nonstop1h 33m

San Francisco

Sun 8/17

10:11 pm-11:40 pm

Nonstop1h 29m

$74

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Sat 8/23

8:50 pm-9:55 pm

Nonstop1h 05m

Las Vegas Harry Reid Intl

Wed 8/27

7:40 pm-8:45 pm

Nonstop1h 05m

$97

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Tue 8/5

6:10 am-7:37 am

Nonstop1h 27m

San Francisco

Tue 8/5

10:45 am-12:14 pm

Nonstop1h 29m

$99

OntarioPortland

ONT - PDX

ONTPDX

Ontario

Mon 8/25

8:25 am-10:49 am

Nonstop2h 24m

Portland

Fri 8/29

7:04 pm-9:27 pm

Nonstop2h 23m

$110

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Fri 8/15

10:03 am-12:53 pm

Nonstop2h 50m

Seattle/Tacoma Intl

Fri 8/22

1:20 pm-4:14 pm

Nonstop2h 54m

$141

OntarioPortland

ONT - PDX

ONTPDX

Ontario

Sat 10/11

11:15 am-1:34 pm

Nonstop2h 19m

Portland

Tue 10/14

2:38 pm-4:53 pm

Nonstop2h 15m

$157

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Wed 8/27

11:39 am-2:19 pm

Nonstop2h 40m

Seattle/Tacoma Intl

Wed 9/3

7:55 am-10:44 am

Nonstop2h 49m

$157

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 9/27

6:00 am-8:45 am

Nonstop2h 45m

Seattle/Tacoma Intl

Tue 9/30

5:20 am-9:26 am

1 stop4h 06m

$167

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Fri 9/5

11:40 am-2:25 pm

Nonstop2h 45m

Seattle/Tacoma Intl

Tue 9/9

8:05 am-10:50 am

Nonstop2h 45m

$187

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/29

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 $326). 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 July 29, 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 July 29, 2025.
Read reviews from past customers who have flown Alaska Airlines, Southwest, and Delta 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.
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Southwest
8.0
Very good
4,238 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Delta
8.0
Very good
7,977 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
Hawaiian Airlines
7.8
Good
2,605 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.
United Airlines
7.4
Good
8,899 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Comfort

7.8

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Overall

8.0

Reviews

1 / 20
10.0
Excellent

Anonymous,Jul 2025

EUG - SEA

Mobility support was fabulous No flight entertainment that I was aware of.

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?

    $30 is the cheapest one-way deal found within the past few days, from Frontier. You may also be able to find cheap deals on Southwest and United Airlines, with prices starting from $49 and $49, respectively.

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

    While some choose either Ontario - Seattle/Tacoma Intl or Ontario - New York John F Kennedy Intl, Ontario - San Francisco 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 $326). 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 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 July 29, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$22Average$150FlexibilityNo cancel feeOn-time65%
FrontierCheapest$35Average$173FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$58Average$397FlexibilityNo cancel feeOn-time69%
Alaska AirlinesCheapest$67Average$310FlexibilityNo cancel feeOn-time75%
DeltaCheapest$85Average$358FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$97Average$385FlexibilityNo cancel feeOn-time63%
JetBlueCheapest$207Average$338FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$245Average$422FlexibilityNo cancel feeOn-time71%

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