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Cheap flights from Ontario to the United States from $29

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Ontario to the United States departing on 10/23. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
0 bags

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Cheap round-trip flights

Frontier Logo
7:30 pm - 8:42 pmONT-LAS
1h 12mnonstop
Frontier Logo
8:49 pm - 9:56 pmLAS-ONT
1h 07mnonstop
$58Frontier
Find Deal
Fri, Oct 3 - Sat, Oct 4
Frontier Logo
10:28 pm - 11:44 pmONT-LAS
1h 16mnonstop
Frontier Logo
11:27 am - 12:43 pmLAS-ONT
1h 16mnonstop
$59Frontier
Find Deal
Fri, Oct 3 - Sat, Oct 4
Southwest Logo
8:45 pm - 9:50 pmONT-LAS
1h 05mnonstop
Southwest Logo
10:00 pm - 11:00 pmLAS-ONT
1h 00mnonstop
$77Southwest
Find Deal
Sat, Oct 11 - Mon, Oct 13
United Airlines Logo
9:36 am - 10:55 amONT-SFO
1h 19mnonstop
United Airlines Logo
4:20 pm - 5:40 pmSFO-ONT
1h 20mnonstop
$77United Airlines
Find Deal
Fri, Oct 17 - Tue, Oct 21
United Airlines Logo
6:36 pm - 7:55 pmONT-SFO
1h 19mnonstop
United Airlines Logo
9:30 pm - 10:52 pmSFO-ONT
1h 22mnonstop
$94United Airlines
Find Deal
Wed, Oct 22 - Wed, Oct 22
Southwest Logo
9:10 pm - 10:15 pmONT-LAS
1h 05mnonstop
Southwest Logo
7:45 am - 12:55 pmLAS-ONT
5h 10m1 stop
$97Southwest
Find Deal
Tue, Oct 14 - Tue, Oct 21
Delta Logo
5:50 pm - 8:49 pmONT-SEA
2h 59mnonstop
Delta Logo
2:24 pm - 5:10 pmSEA-ONT
2h 46mnonstop
$133Delta
Find Deal
Thu, Oct 16 - Tue, Oct 21
Delta Logo
5:50 pm - 8:49 pmONT-SEA
2h 59mnonstop
Delta Logo
2:19 pm - 5:09 pmSEA-ONT
2h 50mnonstop
$134Delta
Find Deal
Fri, Nov 7 - Sun, Nov 9
American Airlines Logo
11:59 pm - 4:46 amONT-DFW
2h 47mnonstop
American Airlines Logo
9:14 am - 10:07 amDFW-ONT
2h 53mnonstop
$159American Airlines
Find Deal
Wed, Oct 22 - Wed, Oct 29
American Airlines Logo
10:38 am - 10:36 pmONT-EWR
8h 58m1 stop
American Airlines Logo
1:42 pm - 8:24 pmEWR-ONT
9h 42m1 stop
$229American Airlines
Find Deal
Sat, Feb 14 - Sat, Feb 21

United Airlines flights from Ontario to United States

Our best United Airlines deals on Ontario to United States flight tickets
United Airlines
Oct 17
ONT9:36 amOntario
1h 19m
SFO10:55 amSan Francisco
Oct 21
SFO4:20 pmSan Francisco
1h 20m
ONT5:40 pmOntario
$77
Find similar
United Airlines
Oct 22
ONT6:36 pmOntario
1h 19m
SFO7:55 pmSan Francisco
Oct 22
SFO9:30 pmSan Francisco
1h 22m
ONT10:52 pmOntario
$94
Find similar
United Airlines
Dec 24
ONT6:00 amOntario
1h 47m
SFO7:47 amSan Francisco
Dec 31
SFO9:10 pmSan Francisco
1h 23m
ONT10:33 pmOntario
$97
Find similar

Frontier flights from Ontario to United States

Our best Frontier deals on Ontario to United States flight tickets
Frontier
Oct 3
ONT7:30 pmOntario
1h 12m
LAS8:42 pmLas Vegas Harry Reid Intl
Oct 4
LAS8:49 pmLas Vegas Harry Reid Intl
1h 07m
ONT9:56 pmOntario
$58
Find similar
Frontier
Oct 3
ONT10:28 pmOntario
1h 16m
LAS11:44 pmLas Vegas Harry Reid Intl
Oct 4
LAS11:27 amLas Vegas Harry Reid Intl
1h 16m
ONT12:43 pmOntario
$59
Find similar
Frontier
Oct 2
ONT6:00 amOntario
1h 11m
LAS7:11 amLas Vegas Harry Reid Intl
Oct 7
LAS7:33 pmLas Vegas Harry Reid Intl
1h 09m
ONT8:42 pmOntario
$62
Find similar

momondo Fare Finder

 
Customize your flight search to find flights from Ontario to United States 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, momondo users made 832,500 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

Fly to

Route

Depart

Return

Price

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Fri 10/3

7:30 pm-8:42 pm

Nonstop1h 12m

Las Vegas Harry Reid Intl

Sat 10/4

8:49 pm-9:56 pm

Nonstop1h 07m

$58

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Fri 10/3

10:28 pm-11:44 pm

Nonstop1h 16m

Las Vegas Harry Reid Intl

Sat 10/4

11:27 am-12:43 pm

Nonstop1h 16m

$59

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Sat 10/11

8:45 pm-9:50 pm

Nonstop1h 05m

Las Vegas Harry Reid Intl

Mon 10/13

10:00 pm-11:00 pm

Nonstop1h 00m

$77

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Fri 10/17

9:36 am-10:55 am

Nonstop1h 19m

San Francisco

Tue 10/21

4:20 pm-5:40 pm

Nonstop1h 20m

$77

OntarioSan Francisco

ONT - SFO

ONTSFO

Ontario

Wed 10/22

6:36 pm-7:55 pm

Nonstop1h 19m

San Francisco

Wed 10/22

9:30 pm-10:52 pm

Nonstop1h 22m

$94

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Tue 10/14

9:10 pm-10:15 pm

Nonstop1h 05m

Las Vegas Harry Reid Intl

Tue 10/21

7:45 am-12:55 pm

1 stop5h 10m

$97

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Thu 10/16

5:50 pm-8:49 pm

Nonstop2h 59m

Seattle/Tacoma Intl

Tue 10/21

2:24 pm-5:10 pm

Nonstop2h 46m

$133

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Fri 11/7

5:50 pm-8:49 pm

Nonstop2h 59m

Seattle/Tacoma Intl

Sun 11/9

2:19 pm-5:09 pm

Nonstop2h 50m

$134

OntarioDallas

ONT - DFW

ONTDFW

Ontario

Wed 10/22

11:59 pm-4:46 am

Nonstop2h 47m

Dallas/Fort Worth

Wed 10/29

9:14 am-10:07 am

Nonstop2h 53m

$159

OntarioNewark

ONT - EWR

ONTEWR

Ontario

Sat 2/14

10:38 am-10:36 pm

1 stop8h 58m

Newark

Sat 2/21

1:42 pm-8:24 pm

1 stop9h 42m

$229

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to the United States from

How to get the cheapest flight ticket from Ontario to United States

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the cheapest month to fly to United States?

In general, January is the cheapest month to fly from Ontario to United States. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $276. If you aren’t able to travel during the month of January, then book flights to United States from Ontario during September instead. Flights to United States in September, while not as cheap as those in January, still average around $316.

What is the cheapest day to depart on your flight to United States?

According to our data, Saturday is the cheapest day to fly to United States from Ontario. The lowest ticket price found for a Saturday departure recently was $334. Keep in mind that prices can always vary depending on your route and whether or not you are flying domestic or international. If your travel schedule is flexible, try to avoid departing on a Wednesday because tickets tend to average around $385. These prices are subject to change though, so be sure to set up a Price Alert for flights to United States.

What is the cheapest time of day to depart on your flight to United States?

The cheapest time of day to fly to United States is in the afternoon when flights can be purchased for as low as $309. Try not to purchase tickets in the evening because they tend to be around $356. Of course, these prices can vary depending on the time of year and what airport you fly to.

What is the cheapest Ontario to United States flight route?

Fly from Ontario to Las Vegas Harry Reid Intl for the best Ontario - United States flight prices

How far in advance should I book a flight to United States?

You are more likely to see cheaper flights to United States from Ontario when booking weeks ahead of your departure date. In general, you can expect to find flights to United States for around $348 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to United States from Ontario for as low as $272 on momondo.

What cabin class options are available on Ontario to United States flights?

There are 4 cabin classes available to choose from on Ontario to United States flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on Ontario to United States flights?

No. A direct flight is the cheapest option for a flight between Ontario to United States.

Cheap Ontario to United States flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from Ontario to United States

Best Price Found

$69

Fastest flight time

1h 00m

Direct flights

Every day

Airports in United States

1 airport
The best one-way flight to United States from Ontario in the past 72 hours is $69. The best round-trip flight deal from Ontario to United States found on momondo in the last 72 hours is $99.
The fastest flight from Ontario to United States takes 1h 00m
Direct flights go from Ontario to United States every day.
There is 1 airport near United States: Las Vegas Harry Reid Intl (LAS)
Search flight deals

  • When did momondo last update prices for flights from Ontario Airport to United States?

    Prices for flights from Ontario Airport to United States refresh daily.

  • How many operators does momondo search for flights from Ontario Airport to United States?

  • How old do you have to be to fly from Ontario Airport to United States?

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Ontario Airport to United States.

  • What documentation or ID do you need to fly to United States?

    The necessary travel and health documents for your United States trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

  • What is the most popular plane model from Ontario to United States?

Best airlines flying from Ontario to United States

Compare and see reviews for airlines that fly from Ontario to United States with momondo
Airline
Rating
Free Cancellation
Price
Spirit AirlinesPriceFrom $22Free CancellationRating
6.3
8,023 reviews
Search Spirit Airlines flights
FrontierPriceFrom $36Free CancellationRating
5.8
3,173 reviews
Search Frontier flights
United AirlinesPriceFrom $58Free CancellationRating
7.4
8,926 reviews
Search United Airlines flights
Alaska AirlinesPriceFrom $67Free CancellationRating
8.0
10,000 reviews
Search Alaska Airlines flights
DeltaPriceFrom $97Free CancellationRating
7.9
7,961 reviews
Search Delta flights
SouthwestPriceFrom $97Free CancellationRating
8.0
4,242 reviews
Search Southwest flights
JetBluePriceFrom $223Free CancellationRating
7.2
2,914 reviews
Search JetBlue flights
American AirlinesPriceFrom $237Free CancellationRating
7.2
10,000 reviews
Search American Airlines flights

Why use momondo?

Why should I use momondo to find a flight deal from Ontario to United States?

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from Ontario to United States for you.

Can I find flights from Ontario to United States with flexible booking policies on momondo?

Yes. All flights to United States from Ontario on momondo can be compared and filtered by various policies on offer, including flexible booking.

How can momondo help me find flights from Ontario to United States?

Once you have performed a search in the form on the page, momondo provides useful filters and insights. We can show you the cheapest days and times to fly as well as help filter your options to help you make an informed choice when booking flights to United States from Ontario.

I’m not ready to book a flight from Ontario to United States right now. Can momondo alert me if prices change?

If you are simply researching potential flights to United States, momondo offers a useful price alert feature which will track prices for flights to United States from Ontario and alert you when they change.

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1 adult
Fri 10/17
Fri 10/24
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