$185 Cheap Flights from Ontario (ONT) to Islip (ISP)

View $185 flight on Tue, Nov 18, 2025Opens in a new window

Popular airlines from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP)

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Cheap Flights from Ontario to Islip (ONT-ISP)

Prices were available within the past 7 days and start at $185 for one-way flights and $369 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Southwest Airlines
Sat, Nov 15 - Wed, Nov 19
ONT
Ontario
ISP
Islip
$369 Roundtrip, found 2 days ago
$369
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Sat, Nov 15 from Ontario to Islip, returning Wed, Nov 19, priced at $369 found 2 days ago
Southwest Airlines
Sat, Nov 15 - Wed, Nov 19
ONT
Ontario
ISP
Islip
$374 Roundtrip, found 2 days ago
$374
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Sat, Nov 15 from Ontario to Islip, returning Wed, Nov 19, priced at $374 found 2 days ago
Southwest Airlines
Sat, Nov 15 - Wed, Nov 19
ONT
Ontario
ISP
Islip
$380 Roundtrip, found 2 days ago
$380
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Sat, Nov 15 from Ontario to Islip, returning Wed, Nov 19, priced at $380 found 2 days ago
Southwest Airlines
Sat, Nov 15 - Wed, Nov 19
ONT
Ontario
ISP
Islip
$385 Roundtrip, found 2 days ago
$385
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Sat, Nov 15 from Ontario to Islip, returning Wed, Nov 19, priced at $385 found 2 days ago
Southwest Airlines
Sat, Nov 15 - Wed, Nov 19
ONT
Ontario
ISP
Islip
$449 Roundtrip, found 2 days ago
$449
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Sat, Nov 15 from Ontario to Islip, returning Wed, Nov 19, priced at $449 found 2 days ago
Southwest Airlines
Sat, Nov 15 - Wed, Nov 19
ONT
Ontario
ISP
Islip
$454 Roundtrip, found 2 days ago
$454
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Sat, Nov 15 from Ontario to Islip, returning Wed, Nov 19, priced at $454 found 2 days ago
Southwest Airlines
Sat, Nov 15 - Wed, Nov 19
ONT
Ontario
ISP
Islip
$460 Roundtrip, found 2 days ago
$460
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Sat, Nov 15 from Ontario to Islip, returning Wed, Nov 19, priced at $460 found 2 days ago
Southwest Airlines
Sat, Nov 15 - Wed, Nov 19
ONT
Ontario
ISP
Islip
$465 Roundtrip, found 2 days ago
$465
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Sat, Nov 15 from Ontario to Islip, returning Wed, Nov 19, priced at $465 found 2 days ago
Southwest Airlines
Fri, Nov 28 - Fri, Dec 5
ONT
Ontario
ISP
Islip
$466 Roundtrip, found 2 days ago
$466
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Fri, Nov 28 from Ontario to Islip, returning Fri, Dec 5, priced at $466 found 2 days ago
Southwest Airlines
Fri, Nov 28 - Fri, Dec 5
ONT
Ontario
ISP
Islip
$472 Roundtrip, found 2 days ago
$472
Roundtrip
found 2 days ago
Select Southwest Airlines flight, departing Fri, Nov 28 from Ontario to Islip, returning Fri, Dec 5, priced at $472 found 2 days ago

Frequently asked questions

How much does a flight from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP) cost?
Grab a cheap one-way flight from $185 or cheap return flight from $369 from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight offers on this route.
What is the cheapest month to fly from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP)?
The cheapest month to fly from ONT to ISP is November, when there's less demand. Off-peak season is generally when better flight deals are available between these airports.
What is the cheapest airline that flies from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP)?
Use the filters on Expedia to compare airlines and find the most affordable carrier that'll fly you from ONT to ISP. Then, sort your results by "Price (lowest to highest)" to pick up a good deal.
How many flights per day from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP)?
You'll have to take a flight with a layover when traveling from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP). Direct flights don't operate daily on this route. However, simply filter your search to include one or more stops to find the best option for your trip.
What day of the week has the most flights from ONT to ISP?
You'll usually find Tuesday the quietest day for flights, while Fridays tend to be the busiest.* However this can change from season to season and during public holidays or peak travel times.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP)?
To touch down at MacArthur Airport (ISP) on schedule, select a flight that leaves from Los Angeles - Ontario Intl. Airport (ONT) before 3 PM. The likelihood of cancellations is 22% higher, on average, for departures after this hour.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP) last-minute?
Last-minute fares from ONT to ISP are typically more expensive. To secure the best prices, start searching for flights as soon as possible. That being said, if you're flexible with your travel dates, it's possible to find a cheap ticket just before your departure.
Is it cheaper to book an ONT to ISP flight and hotel package?
Booking an ONT to ISP flight and hotel package is typically cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your trip in one place. Select from our extensive range of accommodations and then add activities, flights and car rentals to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Los Angeles - Ontario Intl. Airport (ONT) to MacArthur Airport (ISP)?
Typically, you're able to cancel or reschedule your ONT to ISP flight. However, there may be additional fees, especially if you made your booking over 24 hours ago. Check your itinerary for the airline's fees and guidelines on flight changes, or if you want further information, go to our Customer Service portal.

Travel information

Origin airport
Los Angeles - Ontario Intl.
Destination airport
MacArthur
Airlines serving
Southwest Airlines
Roundtrip price
$369
Distance
2458 mi

Book with confidence

Ontario to Islip Flights

The cheapest times to fly from Ontario to Islip

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Ontario to Islip are during the month of November. You can find some of the cheapest flights from Ontario to Islip with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Ontario to Islip

Sunday is one of the best days to book for cheap flights from Ontario to Islip: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Ontario to Islip

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Ontario to Islip in 2025. You can also book with separate airlines for your outbound and return journeys, from $185 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Ontario to Islip flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Ontario to Islip airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Ontario to Islip Flights

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*Available to One Key members.