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$79+ Cheap flights from Islip, NY 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 9/15. Fares are subject to change and may not be available on all flights or dates of travel.
ISP — PHL
Aug 23 — Aug 301
Sat 8/23
Sat 8/30
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 August 18, 2025.

Round-trip from

$161
(Frontier)

One-way from

$79
(Frontier)

Popular in

July

Cheapest in

September

Average price

$269
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. 19% potential increase in price ($90 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 August 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 August 18, 2025.

This Frontier deal was found by Cheapflights users on 8/18. 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 9/411:45 amISP - PHL
1 stop13h 07mFrontier
Sun 9/75:01 amPHL - ISP
1 stop11h 26mFrontier
Deal found 8/18$161
This Frontier deal was found by Cheapflights users on 8/16. 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.
Sat 9/611:40 amISP - PHL
1 stop7h 57mFrontier
Sun 9/75:01 amPHL - ISP
1 stop11h 26mFrontier
Deal found 8/16$168
This Orbitz deal was found by Cheapflights users on 8/16. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/1111:25 amISP - PHL
1 stop7h 43mFrontier
Mon 9/155:57 pmPHL - ISP
2 stops16h 43mFrontier
Deal found 8/16$201
This Orbitz deal was found by Cheapflights users on 8/18. 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 Orbitz is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/62:32 pmISP - PHL
2 stops18h 40mFrontier
Tue 10/711:34 amPHL - ISP
1 stop9h 08mFrontier
Deal found 8/18$226
This Expedia deal was found by Cheapflights users on 8/17. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/149:49 amISP - PHL
2 stops11h 43mFrontier
Sun 9/215:01 amPHL - ISP
1 stop11h 26mFrontier
Deal found 8/17$233
This Kiwi.com deal was found by Cheapflights users on 8/17. 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.
Mon 9/17:27 pmISP - PHL
1 stop23h 30mFrontier
Fri 9/510:16 pmPHL - ISP
1 stop12h 39mFrontier
Deal found 8/17$250
This Kiwi.com deal was found by Cheapflights users on 8/17. 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.
Mon 9/17:27 pmISP - PHL
2 stops16h 03mMultiple Airlines
Fri 9/58:43 pmPHL - ISP
1 stop14h 12mMultiple Airlines
Deal found 8/17$263
This Frontier deal was found by Cheapflights users on 8/18. 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 8/266:05 amISP - PHL
1 stop12h 52mFrontier
Wed 9/35:15 pmPHL - ISP
1 stop6h 26mFrontier
Deal found 8/18$271
This Justfly.com deal was found by Cheapflights users on 8/17. 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 Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/256:45 amISP - PHL
1 stop4h 30mFrontier
Tue 8/265:30 pmPHL - ISP
1 stop6h 29mFrontier
Deal found 8/17$368
This Kiwi.com deal was found by Cheapflights users on 8/17. 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.
Tue 9/1611:25 amISP - PHL
1 stop9h 46mFrontier
Tue 9/232:30 pmPHL - ISP
1 stop20h 10mFrontier
Deal found 8/17$380
This Kiwi.com deal was found by Cheapflights users on 8/17. 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.
Tue 9/1611:25 amISP - PHL
2 stops22h 21mMultiple Airlines
Tue 9/232:30 pmPHL - ISP
1 stop20h 10mMultiple Airlines
Deal found 8/17$419

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 August 18, 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

Thu 9/11

11:25 am-7:08 pm

1 stop7h 43m

Philadelphia

Mon 9/15

8:00 am-4:27 pm

1 stop8h 27m

$161

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Thu 9/4

11:45 am-12:52 am

1 stop13h 07m

Philadelphia

Sun 9/7

5:01 am-4:27 pm

1 stop11h 26m

$161

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Mon 10/6

2:32 pm-10:33 pm

1 stop8h 01m

Philadelphia

Tue 10/7

8:00 am-8:42 pm

1 stop12h 42m

$161

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Sun 9/14

5:12 pm-12:59 am

1 stop7h 47m

Philadelphia

Sun 9/21

6:30 pm-10:40 am

1 stop16h 10m

$168

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Sat 9/6

11:40 am-7:37 pm

1 stop7h 57m

Philadelphia

Sun 9/7

5:01 am-4:27 pm

1 stop11h 26m

$168

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Mon 9/1

7:27 pm-6:57 pm

1 stop23h 30m

Philadelphia

Fri 9/5

10:16 pm-10:55 am

1 stop12h 39m

$250

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Mon 9/1

7:27 pm-11:30 am

2 stops16h 03m

Philadelphia

Fri 9/5

8:43 pm-10:55 am

1 stop14h 12m

$263

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Tue 9/16

11:25 am-9:11 pm

1 stop9h 46m

Philadelphia

Tue 9/23

2:30 pm-10:40 am

1 stop20h 10m

$380

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Mon 9/15

5:05 pm-12:52 am

1 stop7h 47m

$79

IslipPhiladelphia

ISP - PHL

ISPPHL

Islip Long Island

Mon 8/25

6:45 am-11:15 am

1 stop4h 30m

$93

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/17

Showing 1-10 of 13 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, New York to Philadelphia?

Currently, August is the cheapest month in which you can book a flight from Islip, New York to Philadelphia (average of $236). Flying from Islip, New York 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, New York to Philadelphia?

    For as low as $161, Frontier can have you in Philadelphia from Islip, New York in 7h 43m. The distance between Islip, New York and Philadelphia is about 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, New York to Philadelphia?

    Currently, August is the cheapest month in which you can book a flight from Islip, New York to Philadelphia (average of $236). Flying from Islip, New York 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
Cherry Hill
Ocean City
Reading
Millville
Ephrata
Camden
Dewey Beach
Dover
Elkton
Essington
Willow Grove
Newark
Chester
Exton
Glen Mills
Springfield

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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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