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$138+ Cheap flights from Islip to Philadelphia (ISP - PHL)

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 9/27. Fares are subject to change and may not be available on all flights or dates of travel.
ISP — PHL
Oct 11 — Oct 181
Sat 10/11
Sat 10/18
1 adult, Economy
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Cheap flight deals from Islip to Philadelphia

Discover tips and strategies to find the most affordable flight options for your journey from Islip (ISP) to Philadelphia (PHL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated September 11, 2025.

Round-trip from

$158
(Frontier)

One-way from

$138
(Kiwi.com)

Popular in

July

Cheapest in

September

Average price

$169
From Islip Long Island to Philadelphia
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One-way flight from Islip Long Island to Philadelphia
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Highest demand for flights based on searches. 20% potential increase in price ($93 potential increase over avg. RT price).
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Cheapest flight prices on average. 9% potential price decrease ($32 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from Islip to Philadelphia

Cheapest flights from Islip to Philadelphia
Explore the most affordable flight options available from Islip to Philadelphia. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 11, 2025.

This Frontier deal was found by Cheapflights users on 9/8. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 9/3011:25 amISP - PHL
1 stop9h 46mFrontier
Tue 10/711:34 amPHL - ISP
1 stop9h 08mFrontier
Deal found 9/8$158
This Frontier deal was found by Cheapflights users on 9/10. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/255:12 pmISP - PHL
1 stop7h 47mFrontier
Mon 9/2910:16 pmPHL - ISP
1 stop12h 24mFrontier
Deal found 9/10$161
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/84:58 pmISP - PHL
1 stop14h 32mFrontier
Wed 10/159:14 pmPHL - ISP
1 stop23h 28mFrontier
Deal found 9/10$179
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/38:09 pmISP - PHL
1 stop11h 20mMultiple Airlines
Wed 12/1010:46 amPHL - ISP
1 stop8h 28mMultiple Airlines
Deal found 9/10$239
This Frontier deal was found by Cheapflights users on 9/11. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/211:40 amISP - PHL
1 stop13h 12mFrontier
Thu 10/911:16 amPHL - ISP
1 stop9h 26mFrontier
Deal found 9/11$252
This Frontier deal was found by Cheapflights users on 9/9. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/1011:22 amISP - PHL
1 stop6h 10mFrontier
Sun 10/1211:45 amPHL - ISP
1 stop9h 07mFrontier
Deal found 9/9$262
This Kiwi.com deal was found by Cheapflights users on 9/9. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/411:40 amISP - PHL
2 stops12h 07mMultiple Airlines
Wed 10/89:14 pmPHL - ISP
1 stop23h 28mMultiple Airlines
Deal found 9/9$277
This Kiwi.com deal was found by Cheapflights users on 9/10. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/84:58 pmISP - PHL
1 stop14h 32mFrontier
Sat 10/117:10 pmPHL - ISP
2 stops25h 42mFrontier
Deal found 9/10$278
This Frontier deal was found by Cheapflights users on 9/8. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/199:49 amISP - PHL
1 stop12h 44mFrontier
Sun 9/215:01 amPHL - ISP
1 stop11h 26mFrontier
Deal found 9/8$279
This Kiwi.com deal was found by Cheapflights users on 9/9. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/411:40 amISP - PHL
1 stop7h 57mFrontier
Wed 10/89:14 pmPHL - ISP
1 stop23h 28mFrontier
Deal found 9/9$293

Cheapflights Fare Finder

 
Customize your flight search to find flights from Islip to Philadelphia 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 September 11, 2025.
Use the filters below to find and compare flights from Islip to Philadelphia that are best for you.

Fly from

Islip

Fly to

Philadelphia

Route

Depart

Return

Price

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Tue 9/30

11:25 am-9:11 pm

1 stop9h 46m

Philadelphia

Tue 10/7

11:34 am-8:42 pm

1 stop9h 08m

$158

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Thu 9/25

5:12 pm-12:59 am

1 stop7h 47m

Philadelphia

Mon 9/29

10:16 pm-10:40 am

1 stop12h 24m

$161

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Wed 12/3

8:09 pm-7:29 am

1 stop11h 20m

Philadelphia

Wed 12/10

10:46 am-7:14 pm

1 stop8h 28m

$239

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Wed 10/8

4:58 pm-11:26 am

1 stop18h 28m

Philadelphia

Wed 10/15

5:53 pm-9:04 am

2 stops15h 11m

$248

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Thu 10/2

11:40 am-12:52 am

1 stop13h 12m

Philadelphia

Thu 10/9

11:16 am-8:42 pm

1 stop9h 26m

$252

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Fri 10/10

11:22 am-5:32 pm

1 stop6h 10m

Philadelphia

Sun 10/12

11:45 am-8:52 pm

1 stop9h 07m

$262

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Sat 10/4

11:40 am-11:47 pm

2 stops12h 07m

Philadelphia

Wed 10/8

9:14 pm-8:42 pm

1 stop23h 28m

$277

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Wed 10/8

4:58 pm-7:30 am

1 stop14h 32m

Philadelphia

Sat 10/11

7:10 pm-8:52 pm

2 stops25h 42m

$278

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Fri 9/19

9:49 am-10:33 pm

1 stop12h 44m

Philadelphia

Sun 9/21

5:01 am-4:27 pm

1 stop11h 26m

$279

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Sat 10/4

11:40 am-7:37 pm

1 stop7h 57m

Philadelphia

Wed 10/8

9:14 pm-8:42 pm

1 stop23h 28m

$293

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/8

Showing 1-10 of 14 results
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Best time to book a flight from Islip to Philadelphia

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

What is the cheapest month to book a flight from Islip to Philadelphia?

Currently, August is the cheapest month in which you can book a flight from Islip to Philadelphia (average of $236). Flying from Islip to Philadelphia in March is currently the most expensive (average of $295). 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.

Related info for your journey

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

  • How long is the flight from Islip to Philadelphia?

    For as low as $158, Frontier can have you in Philadelphia from Islip in 9h 46m. Airlines will cover a distance of 129 mi.

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

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

  • How can I find direct flights from Islip to Philadelphia?

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

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

    Yes. Cheapflights offers flight deals from Islip to Philadelphia 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 Islip to Philadelphia?

    Currently, August is the cheapest month in which you can book a flight from Islip to Philadelphia (average of $236). Flying from Islip to Philadelphia in March is currently the most expensive (average of $295). 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

Traveling to a place near Philadelphia?

Book flights to Philadelphia if you plan to visit one of these locations
Vineland
Wildwood
King of Prussia
Pottstown
Reading
Dewey Beach
Ephrata
Camden
Ocean City
Cherry Hill
Dover
Elkton
Essington
Willow Grove
Newark
Millville
Chester
Exton
Havre de Grace
Plymouth Meeting

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Alternative routes for Islip to Philadelphia

See prices for flight routes from nearby airports that may be better suited for you.
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