HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Islip

$110+ Cheap flights from St. Louis to Islip, NY (STL - ISP)

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.
STL — ISP
Aug 23 — Aug 301
Sat 8/23
Sat 8/30
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

Find cheap flights from St. Louis to Islip with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheap flight deals from St. Louis to Islip

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Islip (ISP). 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

$260
(Southwest)

One-way from

$110
(Southwest)

Popular in

March

Cheapest in

April

Average price

$366
From Lambert-St Louis to Islip Long Island
Search Deals
One-way flight from Lambert-St Louis to Islip Long Island
Search Deals
High demand for flights, 4% potential price rise
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($12 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in August 2025
Search Deals

Find flight deals from St. Louis to Islip

Cheapest flights from St. Louis to Islip
Explore the most affordable flight options available from St. Louis to Islip. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 18, 2025.

This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/17:00 amSTL - ISP
1 stop7h 10mSouthwest
Sun 10/56:30 pmISP - STL
1 stop6h 00mSouthwest
Deal found 8/17$260
This Priceline 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/212:02 pmSTL - ISP
1 stop8h 57mFrontier
Mon 8/258:59 amISP - STL
1 stop6h 22mFrontier
Deal found 8/16$262
This Frontier 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/227:54 pmSTL - ISP
2 stops17h 05mFrontier
Sun 8/247:43 pmISP - STL
2 stops18h 13mFrontier
Deal found 8/17$357
This Southwest 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/211:30 pmSTL - ISP
2 stops8h 25mSouthwest
Mon 8/256:00 amISP - STL
2 stops8h 25mSouthwest
Deal found 8/16$682
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.
Thu 8/282:02 pmSTL - ISP
1 stop8h 57mFrontier
Sun 8/316:05 amISP - STL
1 stop8h 02mFrontier
Deal found 8/16$910

Cheapflights Fare Finder

 
Customize your flight search to find flights from St. Louis to Islip 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 St. Louis to Islip that are best for you.

Fly from

St. Louis

Fly to

Islip

Route

Depart

Return

Price

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Wed 10/1

7:00 am-3:10 pm

1 stop7h 10m

Islip Long Island

Sun 10/5

6:30 pm-11:30 pm

1 stop6h 00m

$260

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 8/28

2:02 pm-11:59 pm

1 stop8h 57m

Islip Long Island

Sun 8/31

6:05 am-1:07 pm

1 stop8h 02m

$910

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sat 9/27

7:15 am-2:55 pm

1 stop6h 40m

$110

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sun 11/9

11:17 am-8:42 pm

2 stops8h 25m

$111

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Mon 9/29

4:00 pm-10:40 am

2 stops17h 40m

$118

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 9/4

4:00 pm-9:04 am

2 stops16h 04m

$120

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 10/30

8:40 pm-9:09 am

2 stops11h 29m

$121

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Tue 10/14

7:52 pm-9:44 am

2 stops12h 52m

$123

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/17

Best time to book a flight from St. Louis to Islip

Have a flexible travel schedule? Discover the best time to fly to Islip from St. Louis 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 St. Louis to Islip

What is the cheapest month to book a flight from St. Louis to Islip, New York?

Currently, January is the cheapest month in which you can book a flight from St. Louis to Islip, New York (average of $108). Flying from St. Louis 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.

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

Find hourly flight availability from St. Louis to Islip. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated August 18, 2025.

A simple way to save on the total cost of your ticket is to fly from St. Louis to Islip, New York at noon. If you’re flexible enough to do this you can expect to save up to 60% on your trip compared to booking a flight in the morning.

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 August 18, 2025.
Peruse reviews from past customers who have flown with Southwest from St. Louis to Islip to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,246 reviews

Entertainment

7.5

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,246 reviews
Southwest
8.0
Very good
4,246 reviews

Entertainment

7.5

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Comfort

8.0

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from St. Louis to Islip. 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 St. Louis to Islip, New York?

    There are many flights that can get you from St. Louis to Islip, New York in 7h 10m. Fly via Southwest or Frontier to get the fastest option. St. Louis and Islip, New York are separated by a distance of 926 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What is the cheapest airline to fly from St. Louis to Islip, New York round-trip?

    Our cheapest airline available from St. Louis to Islip, New York is Southwest. Our recent data shows that you can find tickets from as low as $339 on this airline. Southwest is priced at 17% lower than the current average price of a flight leaving 3 months from now.

  • Can I find deals for flights from St. Louis to Islip that include hotel bookings?

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

  • How can I find direct flights from St. Louis to Islip?

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

  • Can I find deals for business class flights from St. Louis to Islip?

    Yes. Cheapflights offers flight deals from St. Louis 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 St. Louis to Islip, New York?

    Currently, January is the cheapest month in which you can book a flight from St. Louis to Islip, New York (average of $108). Flying from St. Louis 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.

See more FAQs

Traveling to a place near Islip?

Book flights to Islip if you plan to visit one of these locations
Riverhead
Southampton

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for St. Louis to Islip

See prices for flight routes from nearby airports that may be better suited for you.
St. Louis to LaGuardia flights
Kansas City to LaGuardia flights
St. Louis to Newark flights
St. Louis to John F Kennedy Intl flights
Kansas City to John F Kennedy Intl flights
Kansas City to Newark flights
Springfield to John F Kennedy Intl flights
Springfield to LaGuardia flights
Kansas City to Buffalo flights
Springfield to Newark flights
St. Louis to Syracuse flights
Kansas City to Albany flights
St. Louis to Albany flights
St. Louis to Rochester flights
Kansas City to Syracuse flights
St. Louis to Buffalo flights
Kansas City to White Plains flights
St. Louis to White Plains flights
Kansas City to Rochester flights
Joplin to Newark flights
Joplin to LaGuardia flights
Springfield to Syracuse flights
Springfield to Albany flights
Columbia to Buffalo flights
Springfield to Buffalo flights
Kansas City to Elmira flights
Kansas City to Islip flights
Columbia to LaGuardia flights
Kansas City to Binghamton flights
Kansas City to Stewart flights
Kansas City to Ithaca flights
St. Louis to Stewart flights
Springfield to White Plains flights
Columbia to Newark flights
Columbia to John F Kennedy Intl flights
Kansas City to Watertown flights
Joplin to Syracuse flights
Columbia to Rochester flights
St. Louis to Binghamton flights
St. Louis to Elmira flights
St. Louis to Watertown flights
Kansas City to Plattsburgh flights
Springfield to Islip flights
Columbia to Albany flights
Columbia to Syracuse flights
Springfield to Stewart flights
St. Louis to Ithaca flights

Top airline flying from St. Louis to Islip

Discover the top airline that operate flights from St. Louis to Islip. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated August 18, 2025.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$339Average$396FlexibilityNo cancel feeOn-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.