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Islip

$150+ 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 3/19. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ISP
Apr 11 — Apr 181
Sat 4/11
Sat 4/18
1 adult, Economy
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Cheap 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 March 12, 2026.

This Southwest deal was found by Cheapflights users on 3/8. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/76:35 am
STL
-
ISP
1 stop6h 15m
Southwest
Sat 4/186:00 am
ISP
-
STL
1 stop5h 00m
Southwest
Deal found 3/8$257
This Southwest deal was found by Cheapflights users on 3/7. 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 6/65:05 am
STL
-
ISP
1 stop8h 00m
Southwest
Wed 6/104:40 pm
ISP
-
STL
1 stop6h 45m
Southwest
Deal found 3/7$282
This Frontier deal was found by Cheapflights users on 3/9. 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.
Thu 3/199:05 pm
STL
-
ISP
1 stop11h 58m
Frontier
Mon 3/231:22 pm
ISP
-
STL
1 stop10h 57m
Frontier
Deal found 3/9$315
This Kiwi.com deal was found by Cheapflights users on 3/8. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/711:21 am
STL
-
ISP
2 stops22h 49m
Multiple Airlines
Sun 4/194:07 pm
ISP
-
STL
1 stop8h 12m
Multiple Airlines
Deal found 3/8$395
This Kiwi.com deal was found by Cheapflights users on 3/8. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 4/711:21 am
STL
-
ISP
2 stops22h 49m
Multiple Airlines
Fri 4/174:07 pm
ISP
-
STL
1 stop8h 12m
Multiple Airlines
Deal found 3/8$406
This Kiwi.com deal was found by Cheapflights users on 3/8. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 4/64:59 pm
STL
-
ISP
1 stop22h 59m
Frontier
Fri 4/174:07 pm
ISP
-
STL
2 stops15h 43m
Frontier
Deal found 3/8$432
This Southwest deal was found by Cheapflights users on 3/9. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 3/264:45 pm
STL
-
ISP
1 stop6h 10m
Southwest
Sun 3/295:55 pm
ISP
-
STL
1 stop6h 10m
Southwest
Deal found 3/9$454

Find 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 March 12, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$257
(Southwest)

One-way from

$150
(Frontier)

Popular in

November

Cheapest in

August

Average price

$333
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. 9% potential increase in price ($33 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($6 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in March 2026
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 March 12, 2026.
Use the filters below to find and compare flights from St. Louis to Islip that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip
Quickest round-trip

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Tue 4/7

6:35 am-1:50 pm

1 stop6h 15m

Islip Long Island

Sat 4/18

6:00 am-10:00 am

1 stop5h 00m

$257

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sat 6/6

5:05 am-2:05 pm

1 stop8h 00m

Islip Long Island

Wed 6/10

4:40 pm-10:25 pm

1 stop6h 45m

$282

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Mon 4/6

4:59 pm-4:58 pm

1 stop22h 59m

Islip Long Island

Sun 4/19

4:07 pm-6:50 am

2 stops15h 43m

$432

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Tue 4/7

4:59 pm-4:43 pm

1 stop22h 44m

Islip Long Island

Fri 4/17

4:07 pm-11:19 pm

1 stop8h 12m

$525

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 3/26

8:02 am-4:13 pm

1 stop7h 11m

Islip Long Island

Mon 3/30

1:22 pm-11:19 pm

1 stop10h 57m

$614

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sat 4/11

8:36 am-4:17 pm

1 stop6h 41m

Islip Long Island

Sun 4/12

7:59 pm-7:51 am

1 stop12h 52m

$619

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Wed 4/8

4:59 pm-3:10 pm

1 stop21h 11m

Islip Long Island

Sat 4/18

11:50 am-11:19 pm

2 stops12h 29m

$641

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Fri 4/10

8:41 am-6:49 pm

1 stop9h 08m

Islip Long Island

Mon 4/13

4:01 pm-11:25 pm

1 stop8h 24m

$649

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sun 3/22

9:05 pm-10:03 am

1 stop11h 58m

Islip Long Island

Thu 3/26

5:08 pm-11:19 pm

1 stop7h 11m

$778
Cheapest one-way

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 3/19

8:02 am-3:49 pm

1 stop6h 47m

$150

Flights are sorted by cheapest round-trip flights first.

Deals found on 3/9

Showing 1-10 of 15 resultsSorted by cheapest first
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 March.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice 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 FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Islip, New York flight deals on Cheapflights vs. FlightHub >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 FlightHub the most. FlightHub 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, January is the cheapest month in which you can book a flight from St. Louis to Islip, New York (average of $121). Flying from St. Louis to Islip, New York in March is currently the most expensive (average of $245). 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.

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 March 12, 2026.
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
4,319 reviews

Crew

8.6

Comfort

8.0

Overall

8.0

Food

7.0

Boarding

8.1

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..
Southwest
8.0
Very good
4,319 reviews
Southwest
8.0
Very good
4,319 reviews

Crew

8.6

Comfort

8.0

Overall

8.0

Food

7.0

Boarding

8.1

Entertainment

7.5

Reviews

1 / 20
10.0
Excellent

Anonymous,Mar 2026

KOA - HNL

pretty smooth and fast service ever, that flight is very helpful each and everyone for price and also fright for free..

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 6h 15m. Fly via Southwest 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 $218 on this airline.

  • 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 $121). Flying from St. Louis to Islip, New York in March is currently the most expensive (average of $245). 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

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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 March 12, 2026.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$218Average$403FlexibilityNo cancel feeOn-time63%

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