How far in advance should I book a flight from Ontario to Islip, New York?

Travelers have found it’s best to book a flight 36 days in advance to save up to 72% compared to booking the same week of travel. As your travel date approaches, the cost of this flight route may potentially increase. While opting to book 36 days out may not be an option for all, there are still additional ways to secure a deal in the near future. You might find a flight from Ontario to Islip, New York 1-2 weeks in advance for as low as $397, or $656 for flights within the next 24 hours.

What is the cheapest month to fly from Ontario to Islip, New York?

Flights from Ontario to Islip, New York lean towards being more expensive in December. Prices are generally better when you fly from Ontario to Islip, New York in January, with the cheapest ticket starting at $137.

What is the cheapest time of day to fly from ONT to ISP?

When flying from Ontario to Islip, New York, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

Most accurate provider : When it comes to deals on Ontario-Islip, New York flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-Islip, New York flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-Islip, New York flight searches over the past month and is updated monthly.

Most trusted provider : When it comes to deals on Ontario-Islip, New York flights, Cheapflights users trust Expedia the most. Expedia has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-Islip, New York flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Can I find deals for flights from Ontario to Islip that include hotel bookings?

Yes. In addition to deals on Ontario to Islip flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from Ontario to Islip?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to Islip.

Can I find deals for business class flights from Ontario to Islip?

Yes. Cheapflights offers flight deals from Ontario to Islip by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$442+ Flights from Ontario to Islip, NY

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Cheap flight deals from Ontario to Islip

Most accurate provider	FlightHub 3 stars
Most trusted provider	Expedia 3 stars
Round-trip from	$442 (Southwest)
Popular in	December
Cheapest in	January
Average price	$347

Provider with most accurate pricing for Ontario-Islip Long Island flight deals.

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Provider most trusted by Cheapflights users for Ontario-Islip Long Island flights.

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From Ontario to Islip Long Island

Search Deals

Highest demand for flights based on searches. 2% potential increase in price ($11 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 2% potential price decrease ($7 potential savings vs. average RT price).

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Average for round-trip flights in May 2025

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Find flight deals from Ontario to Islip

Cheapest flights from Ontario to Islip
Explore the most affordable flight options available from Ontario to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 12, 2025.

Thu 10/29:00 amONT - ISP

2 stops11h 45mSouthwest

Sat 10/411:55 amISP - ONT

1 stop9h 35mSouthwest

Deal found 5/11

$442

Tue 7/17:00 amONT - ISP

2 stops33h 36mFrontier

Tue 7/88:21 pmISP - ONT

2 stops28h 31mFrontier

Deal found 5/12

$521

Best flights from Ontario to Islip
Discover carefully curated flight deals from Ontario to Islip that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated May 12, 2025.

Thu 10/29:00 amONT - ISP

2 stops11h 45mSouthwest

Sat 10/411:55 amISP - ONT

1 stop9h 35mSouthwest

Deal found 5/11

$442

Tue 7/17:00 amONT - ISP

2 stops33h 36mFrontier

Tue 7/88:21 pmISP - ONT

2 stops28h 31mFrontier

Deal found 5/12

$521

Cheapflights Fare Finder

Use the filters below to find and compare flights from Ontario to Islip that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

OntarioIslip

ONT - ISP

ONTISP

Ontario

Thu 10/2

9:00 am-11:45 pm

2 stops11h 45m

Islip Long Island

Sat 10/4

11:55 am-6:30 pm

1 stop9h 35m

$442

OntarioIslip

ONT - ISP

ONTISP

Ontario

Tue 7/1

7:00 am-7:36 pm

2 stops33h 36m

Islip Long Island

Tue 7/8

8:21 pm-9:52 pm

2 stops28h 31m

$521

Flights are sorted by cheapest round-trip flights first.

Deals found on 5/11

Compare providers for flights from Ontario to Islip

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to Islip in May.

Provider	Price Accuracy	Trust Score*
FlightHub	Price Accuracy3 stars	Trust Score*2 stars
Expedia	Price Accuracy1 star	Trust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

Most accurate provider: When it comes to deals on Ontario-Islip, New York flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Ontario-Islip, New York flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Ontario-Islip, New York flight searches over the past month and is updated monthly.
Most trusted provider: When it comes to deals on Ontario-Islip, New York flights, Cheapflights users trust Expedia the most. Expedia has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Ontario-Islip, New York flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Ontario to Islip

Have a flexible travel schedule? Discover the best time to fly to Islip 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 Islip

What is the cheapest month to book a flight from Ontario to Islip, New York?

Currently, January is the cheapest month in which you can book a flight from Ontario to Islip, New York (average of $108). Flying from Ontario to Islip, New York in November is currently the most expensive (average of $213). 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.

Rainfall in Islip by month

In terms of precipitation, rainfall in Islip, New York ranges from 3.3 - 4.4 inches per month. March is typically the wettest month, when rainfall can reach 4.4 in. February is typically the driest time to visit Islip, New York when rainfall is around 3.3 in.

Temperature in Islip by month

If weather is an important factor for your trip to Islip, New York, 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 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

Reviews of airlines servicing Islip

Southwest

8.0

Very good

4,290 reviews

Reviews

1 / 20

10.0

Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.

Southwest

8.0

Very good

4,290 reviews

Southwest

8.0

Very good

4,290 reviews

Reviews

1 / 20

10.0

Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.

Frontier

6.0

Okay

3,286 reviews

Southwest

8.0

Very good

4,290 reviews

Reviews

1 / 20

10.0

Excellent

Merlyn,Feb 2025

LAX - SMF

New Terminal is neat, lost of stores and places to catch a bite.

Related info for your journey

Can I find deals for flights from Ontario to Islip that include hotel bookings?
Yes. In addition to deals on Ontario to Islip flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from Ontario to Islip?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Ontario to Islip.
Can I find deals for business class flights from Ontario to Islip?
Yes. Cheapflights offers flight deals from Ontario to Islip 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 Islip, New York?
Currently, January is the cheapest month in which you can book a flight from Ontario to Islip, New York (average of $108). Flying from Ontario to Islip, New York in November is currently the most expensive (average of $213). 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.

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$442+ Cheap flights from Ontario to Islip, NY (ONT - ISP)

This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/2. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from Ontario to Islip with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from Ontario to Islip

Most accurate provider

Most trusted provider

Round-trip from

Popular in

Cheapest in

Average price

Find flight deals from Ontario to Islip

Cheapest flights from Ontario to IslipExplore the most affordable flight options available from Ontario to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 12, 2025.

Explore the most affordable flight options available from Ontario to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 12, 2025.

Cheapflights Fare Finder

Use the filters below to find and compare flights from Ontario to Islip that are best for you.

Compare providers for flights from Ontario to Islip

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Ontario to Islip in May.

Best time to book a flight from Ontario to Islip

Have a flexible travel schedule? Discover the best time to fly to Islip from Ontario with our price prediction graph.

Cheapflights Insights

Everything you need to know about your flight from Ontario to Islip

What is the cheapest month to book a flight from Ontario to Islip, New York?

Rainfall in Islip by month

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

Temperature in Islip by month

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

Reviews of airlines servicing Islip

Get insights into the airlines that provide service to Islip. 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 Islip. Reviews last updated May 12, 2025.

Related info for your journey

Find useful and relevant information for your journey from Ontario to Islip. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

Can I find deals for flights from Ontario to Islip that include hotel bookings?

How can I find direct flights from Ontario to Islip?

Can I find deals for business class flights from Ontario to Islip?

What is the cheapest month to book a flight from Ontario to Islip, New York?

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Cheapest flights from Ontario to Islip
Explore the most affordable flight options available from Ontario to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on May 12, 2025.