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Cheap flights from Ontario to the United States from $34

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 2/15. 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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Find the cheapest flights from Ontario to the United States

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
6:49 pm - 7:58 pm
ONT
-
LAS
1h 09mnonstop
Frontier Logo
6:42 pm - 7:50 pm
LAS
-
ONT
1h 08mnonstop
$60Frontier
Wed, Jan 14 - Sat, Jan 17
Frontier Logo
3:07 pm - 4:19 pm
ONT
-
LAS
1h 12mnonstop
Frontier Logo
5:30 pm - 6:40 pm
LAS
-
ONT
1h 10mnonstop
$61Frontier
Wed, Jan 21 - Sat, Jan 24
Alaska Airlines Logo
11:53 am - 2:44 pm
ONT
-
SEA
2h 51mnonstop
Alaska Airlines Logo
9:20 pm - 11:56 pm
SEA
-
ONT
2h 36mnonstop
$119Alaska Airlines
Sat, Jan 24 - Fri, Jan 30
Delta Logo
3:30 pm - 6:35 pm
ONT
-
SEA
3h 05mnonstop
Delta Logo
7:00 pm - 11:58 pm
SEA
-
ONT
4h 58m1 stop
$129Delta
Sat, Jan 24 - Thu, Jan 29
Alaska Airlines Logo
4:02 pm - 6:52 pm
ONT
-
SEA
2h 50mnonstop
Alaska Airlines Logo
8:05 pm - 10:44 pm
SEA
-
ONT
2h 39mnonstop
$138Alaska Airlines
Sat, Mar 7 - Tue, Mar 10
Delta Logo
1:11 pm - 6:29 pm
ONT
-
SEA
5h 18m1 stop
Delta Logo
5:30 am - 12:16 pm
SEA
-
ONT
6h 46m1 stop
$139Delta
Sat, Jan 24 - Wed, Jan 28
American Airlines Logo
6:00 am - 4:07 pm
ONT
-
LGA
7h 07m1 stop
American Airlines Logo
10:35 am - 6:45 pm
LGA
-
ONT
11h 10m1 stop
$187American Airlines
Tue, Feb 3 - Tue, Feb 10
American Airlines Logo
7:16 am - 6:59 pm
ONT
-
LGA
8h 43m1 stop
American Airlines Logo
5:13 pm - 10:48 pm
LGA
-
ONT
8h 35m1 stop
$190American Airlines
Fri, Jan 30 - Tue, Feb 3
Southwest Logo
2:45 pm - 7:40 pm
ONT
-
HOU
2h 55mnonstop
Southwest Logo
10:50 pm - 12:25 am
HOU
-
ONT
3h 35mnonstop
$333Southwest
Thu, Mar 5 - Sat, Mar 7
Southwest Logo
8:25 am - 4:50 pm
ONT
-
HOU
6h 25m1 stop
Southwest Logo
10:50 pm - 12:25 am
HOU
-
ONT
3h 35mnonstop
$343Southwest
Thu, Mar 5 - Sat, Mar 7

Frontier flights from Ontario to United States

Our best Frontier deals on Ontario to United States flight tickets
Frontier
Jan 17
ONT9:10 pmOntario
1h 10m
LAS10:20 pmLas Vegas Harry Reid Intl
Jan 20
LAS12:26 pmLas Vegas Harry Reid Intl
1h 11m
ONT1:37 pmOntario
$60
Find similar
Frontier
Feb 5
ONT8:48 pmOntario
1h 08m
LAS9:56 pmLas Vegas Harry Reid Intl
Feb 6
LAS6:45 pmLas Vegas Harry Reid Intl
1h 08m
ONT7:53 pmOntario
$61
Find similar
Frontier
Jan 22
ONT3:22 pmOntario
1h 12m
LAS4:34 pmLas Vegas Harry Reid Intl
Jan 24
LAS12:23 pmLas Vegas Harry Reid Intl
1h 11m
ONT1:34 pmOntario
$62
Find similar

American Airlines flights from Ontario to United States

Our best American Airlines deals on Ontario to United States flight tickets
American Airlines
Feb 3
ONT6:00 amOntario
8h 17m
1 stop
JFK5:17 pmNew York John F Kennedy Intl
Feb 10
JFK12:25 pmNew York John F Kennedy Intl
8h 55m
1 stop
ONT6:20 pmOntario
$187
Find similar
American Airlines
Jan 30
ONT6:00 amOntario
8h 00m
1 stop
LGA5:00 pmNew York LaGuardia
Feb 3
LGA10:35 amNew York LaGuardia
11h 10m
1 stop
ONT6:45 pmOntario
$190
Find similar
American Airlines
Jan 18
ONT6:00 amOntario
7h 10m
1 stop
LGA4:10 pmNew York LaGuardia
Jan 27
LGA5:13 pmNew York LaGuardia
8h 35m
1 stop
ONT10:48 pmOntario
$191
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 December 28, 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

Wed 1/14

6:49 pm-7:58 pm

Nonstop1h 09m

Las Vegas Harry Reid Intl

Sat 1/17

6:42 pm-7:50 pm

Nonstop1h 08m

$60

OntarioLas Vegas

ONT - LAS

ONTLAS

Ontario

Wed 1/21

3:07 pm-4:19 pm

Nonstop1h 12m

Las Vegas Harry Reid Intl

Sat 1/24

5:30 pm-6:40 pm

Nonstop1h 10m

$61

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 1/24

11:53 am-2:44 pm

Nonstop2h 51m

Seattle/Tacoma Intl

Fri 1/30

9:20 pm-11:56 pm

Nonstop2h 36m

$119

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 1/24

3:30 pm-6:35 pm

Nonstop3h 05m

Seattle/Tacoma Intl

Thu 1/29

7:00 pm-11:58 pm

1 stop4h 58m

$129

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 3/7

4:02 pm-6:52 pm

Nonstop2h 50m

Seattle/Tacoma Intl

Tue 3/10

8:05 pm-10:44 pm

Nonstop2h 39m

$138

OntarioSeattle

ONT - SEA

ONTSEA

Ontario

Sat 1/24

1:11 pm-6:29 pm

1 stop5h 18m

Seattle/Tacoma Intl

Wed 1/28

5:30 am-12:16 pm

1 stop6h 46m

$139

OntarioNew York

ONT - LGA

ONTLGA

Ontario

Tue 2/3

6:00 am-4:07 pm

1 stop7h 07m

New York LaGuardia

Tue 2/10

10:35 am-6:45 pm

1 stop11h 10m

$187

OntarioNew York

ONT - LGA

ONTLGA

Ontario

Fri 1/30

7:16 am-6:59 pm

1 stop8h 43m

New York LaGuardia

Tue 2/3

5:13 pm-10:48 pm

1 stop8h 35m

$190

OntarioHouston

ONT - HOU

ONTHOU

Ontario

Thu 3/5

2:45 pm-7:40 pm

Nonstop2h 55m

Houston Hobby

Sat 3/7

10:50 pm-12:25 am

Nonstop3h 35m

$333

OntarioHouston

ONT - HOU

ONTHOU

Ontario

Thu 3/5

8:25 am-4:50 pm

1 stop6h 25m

Houston Hobby

Sat 3/7

10:50 pm-12:25 am

Nonstop3h 35m

$343

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 $256. If you aren’t able to travel during the month of January, then book flights to United States from Ontario during February instead. Flights to United States in February, while not as cheap as those in January, still average around $286.

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 $335. 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 $387. 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 $359. 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 $347 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 $275 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

$87

Direct flights

Mon, Tue, Wed, Fri, Sat and Sun

Airports in United States

4,296 airports
The best one-way flight to United States from Ontario in the past 72 hours is $87. The best round-trip flight deal from Ontario to United States found on momondo in the last 72 hours is $115.
Direct flights go from Ontario to United States on Monday, Tuesday, Wednesday, Friday, Saturday and Sunday. Airlines offering direct flights are: Southwest, Alaska Airlines and Frontier.
There are 4,296 airports in United States. From Ontario there are direct flights to 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 $24Free CancellationRating
6.3
8,211 reviews
Search Spirit Airlines flights
FrontierPriceFrom $35Free CancellationRating
5.7
3,065 reviews
Search Frontier flights
United AirlinesPriceFrom $58Free CancellationRating
7.4
9,113 reviews
Search United Airlines flights
Alaska AirlinesPriceFrom $67Free CancellationRating
8.0
11,549 reviews
Search Alaska Airlines flights
SouthwestPriceFrom $97Free CancellationRating
8.0
4,256 reviews
Search Southwest flights
DeltaPriceFrom $178Free CancellationRating
7.9
8,019 reviews
Search Delta flights
American AirlinesPriceFrom $184Free CancellationRating
7.2
11,073 reviews
Search American Airlines flights
JetBluePriceFrom $223Free CancellationRating
7.2
2,901 reviews
Search JetBlue 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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