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Islip

$81+ 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 12/3. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ISP
Dec 25 — Jan 11
Thu 12/25
Thu 1/1
1 adult, Economy
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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 November 25, 2025.

This Kiwi.com deal was found by Cheapflights users on 11/25. 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.
Fri 12/129:54 amSTL - ISP
1 stop22h 19mFrontier
Tue 12/168:29 pmISP - STL
1 stop27h 04mFrontier
Deal found 11/25$185
This Frontier deal was found by Cheapflights users on 11/25. 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.
Wed 12/103:30 pmSTL - ISP
1 stop6h 14mFrontier
Sun 12/1411:15 amISP - STL
1 stop12h 18mFrontier
Deal found 11/25$187
This Kiwi.com deal was found by Cheapflights users on 11/25. 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.
Thu 12/113:30 pmSTL - ISP
1 stop27h 04mFrontier
Mon 12/1510:19 amISP - STL
1 stop13h 14mFrontier
Deal found 11/25$204
This Frontier deal was found by Cheapflights users on 11/24. 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 12/59:54 amSTL - ISP
1 stop8h 40mFrontier
Sun 12/711:15 amISP - STL
1 stop12h 18mFrontier
Deal found 11/24$212
This Expedia deal was found by Cheapflights users on 11/25. 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.
Tue 12/304:27 pmSTL - ISP
1 stop23h 10mFrontier
Mon 1/58:24 pmISP - STL
1 stop27h 09mFrontier
Deal found 11/25$213
This Kiwi.com deal was found by Cheapflights users on 11/25. 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.
Fri 12/1210:42 amSTL - ISP
2 stops21h 31mMultiple Airlines
Tue 12/168:29 pmISP - STL
1 stop27h 04mMultiple Airlines
Deal found 11/25$222
This Kiwi.com deal was found by Cheapflights users on 11/25. 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 12/153:30 pmSTL - ISP
1 stop27h 04mFrontier
Wed 12/176:00 amISP - STL
1 stop17h 33mFrontier
Deal found 11/25$293
This Southwest deal was found by Cheapflights users on 11/25. 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.
Sat 12/1310:10 amSTL - ISP
1 stop3h 50mSouthwest
Tue 12/165:40 amISP - STL
2 stops9h 10mSouthwest
Deal found 11/25$322

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 November 25, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$185
(Kiwi.com)

One-way from

$81
(Frontier)

Popular in

March

Cheapest in

October

Average price

$376
Provider with most accurate pricing for Lambert-St Louis-Islip Long Island flight deals.
Search Deals
Provider most trusted by Cheapflights users for Lambert-St Louis-Islip Long Island flights.
Search Deals
From Lambert-St Louis to Islip Long Island
Search Deals
One-way flight from Lambert-St Louis to Islip Long Island
Search Deals
Highest demand for flights based on searches. 6% potential increase in price ($24 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($18 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in November 2025
Search Deals

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 November 25, 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

Fri 12/12

9:54 am-9:13 am

1 stop22h 19m

Islip Long Island

Tue 12/16

8:29 pm-10:33 pm

1 stop27h 04m

$185

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 12/11

3:30 pm-7:34 pm

1 stop27h 04m

Islip Long Island

Mon 12/15

10:19 am-10:33 pm

1 stop13h 14m

$204

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Fri 12/5

9:54 am-7:34 pm

1 stop8h 40m

Islip Long Island

Sun 12/7

11:15 am-10:33 pm

1 stop12h 18m

$212

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Fri 12/12

9:54 am-7:34 pm

1 stop8h 40m

Islip Long Island

Sun 12/14

11:15 am-8:59 am

1 stop22h 44m

$212

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Tue 12/30

4:27 pm-4:37 pm

1 stop23h 10m

Islip Long Island

Mon 1/5

8:24 pm-10:33 pm

1 stop27h 09m

$213

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Mon 12/22

10:40 am-7:40 pm

1 stop8h 00m

Islip Long Island

Mon 12/29

2:04 pm-10:33 pm

1 stop9h 29m

$264

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Mon 12/15

3:30 pm-7:34 pm

1 stop27h 04m

Islip Long Island

Wed 12/17

6:00 am-10:33 pm

1 stop17h 33m

$293

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Mon 12/15

12:05 pm-9:40 pm

1 stop8h 35m

Islip Long Island

Wed 12/17

5:40 am-12:35 pm

2 stops7h 55m

$322

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sat 12/13

6:05 am-12:50 pm

1 stop5h 45m

Islip Long Island

Tue 12/16

5:40 am-3:50 pm

1 stop11h 10m

$322

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Wed 12/3

3:30 pm-10:44 pm

1 stop6h 14m

$81

Flights are sorted by cheapest round-trip flights first.

Deals found on 11/23

Showing 1-10 of 12 results
1
2

Compare providers for flights from St. Louis 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 St. Louis to Islip in November.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice Accuracy3 starsTrust 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 St. Louis-Islip, New York flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on St. Louis-Islip, New York flight deals on Cheapflights vs. eDreams >95% of the time. Price accuracy is based on data collected from St. Louis-Islip, New York flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on St. Louis-Islip, New York flights, Cheapflights users trust eDreams the most. eDreams 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 St. Louis-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 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, August is the cheapest month in which you can book a flight from St. Louis to Islip, New York (average of $129). Flying from St. Louis to Islip, New York in May is currently the most expensive (average of $199). 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 November 25, 2025.

A simple way to save on the total cost of your ticket is to fly from St. Louis to Islip, New York in the evening. If you’re flexible enough to do this you can expect to save up to 59% 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 November 25, 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
4,254 reviews

Boarding

8.1

Entertainment

7.5

Comfort

8.0

Crew

8.6

Overall

8.0

Food

7.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Southwest
8.0
Very good
4,254 reviews
Southwest
8.0
Very good
4,254 reviews

Boarding

8.1

Entertainment

7.5

Comfort

8.0

Crew

8.6

Overall

8.0

Food

7.0

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

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 22h 19m. Fly via Frontier to get the fastest option. St. Louis and Islip, New York are separated by a distance of 926 mi.

  • 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 $259 on this airline. Southwest is priced at 29% 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, August is the cheapest month in which you can book a flight from St. Louis to Islip, New York (average of $129). Flying from St. Louis to Islip, New York in May is currently the most expensive (average of $199). 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
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Alternative routes for St. Louis to Islip

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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 November 25, 2025.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$259Average$366FlexibilityNo cancel feeOn-time63%

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