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 21m. Fly via Frontier or Southwest 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 $259 on this airline. Southwest is priced at 29% lower than the current average price of a flight leaving 3 months from now.

In terms of precipitation, rainfall in Islip, New York ranges from 3.3 - 4.4 inches per month. March is typically the wettest month, when rainfall can reach 4.4 in. February is typically the driest time to visit Islip, New York when rainfall is around 3.3 in.

If weather is an important factor for your trip to Islip, New York, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 73.4 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 30.2 F).

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.

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.

$81+ Flights from St. Louis to Islip, NY

Q: How much does it cost to fly round-trip from St. Louis to Islip, New York?

Airfare is below average for this route at the moment. St. Louis to Islip, New York flights typically cost between $319 and $461 in February. The cheapest round-trip price found within the last 3 days was $180 on Frontier (Feb 27-Mar 6).

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1. Tell us where you want to go

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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

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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 December 3, 2025.

Fri 12/129:54 amSTL - ISP

1 stop8h 40mFrontier

Tue 12/168:29 pmISP - STL

1 stop27h 04mFrontier

Deal found 12/1

$196

Wed 12/173:30 pmSTL - ISP

1 stop8h 08mFrontier

Sun 12/212:04 pmISP - STL

1 stop9h 29mFrontier

Deal found 12/1

$232

Wed 12/33:30 pmSTL - ISP

1 stop6h 14mFrontier

Thu 12/410:19 amISP - STL

1 stop13h 14mFrontier

Deal found 11/30

$264

Fri 12/59:54 amSTL - ISP

1 stop8h 40mFrontier

Fri 1/22:04 pmISP - STL

1 stop9h 29mFrontier

Deal found 12/1

$292

Mon 12/2210:40 amSTL - ISP

1 stop8h 00mFrontier

Tue 12/3012:20 pmISP - STL

1 stop11h 13mFrontier

Deal found 12/1

$293

Fri 12/122:30 pmSTL - ISP

2 stops8h 20mSouthwest

Tue 12/165:40 amISP - STL

2 stops9h 10mSouthwest

Deal found 12/1

$505

Mon 12/2210:40 amSTL - ISP

1 stop8h 00mFrontier

Mon 12/292:04 pmISP - STL

1 stop9h 29mFrontier

Deal found 12/1

$667

Best flights from St. Louis to Islip
Discover carefully curated flight deals from St. Louis to Islip that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated December 3, 2025.

Fri 2/278:45 amSTL - ISP

1 stop6h 21mFrontier

Fri 3/68:19 pmISP - STL

1 stop11h 54mFrontier

Deal found 12/2

$180

Fri 2/2710:42 amSTL - ISP

2 stops22h 58mMultiple Airlines

Fri 3/68:19 pmISP - STL

1 stop11h 54mMultiple Airlines

Deal found 12/2

$262

Fri 2/275:50 amSTL - ISP

2 stops10h 10mSouthwest

Fri 3/66:00 amISP - STL

2 stops9h 30mSouthwest

Deal found 12/2

$337

Wed 12/173:30 pmSTL - ISP

1 stop8h 08mFrontier

Sun 12/212:04 pmISP - STL

1 stop9h 29mFrontier

Deal found 12/1

$232

Mon 12/2210:40 amSTL - ISP

1 stop8h 00mFrontier

Tue 12/3012:20 pmISP - STL

1 stop11h 13mFrontier

Deal found 12/1

$293

Mon 12/2210:40 amSTL - ISP

1 stop8h 00mFrontier

Mon 12/292:04 pmISP - STL

1 stop9h 29mFrontier

Deal found 12/1

$667

Last-minute flights from St. Louis to Islip
Discover last-minute flight deals from St. Louis to Islip. Data last updated December 3, 2025 and is based on user searches.

Wed 12/33:30 pmSTL - ISP

1 stop6h 14mFrontier

Thu 12/410:19 amISP - STL

1 stop13h 14mFrontier

Deal found 11/30

$264

Fri 12/59:54 amSTL - ISP

1 stop8h 40mFrontier

Fri 1/22:04 pmISP - STL

1 stop9h 29mFrontier

Deal found 12/1

$292

Fri 12/129:54 amSTL - ISP

1 stop8h 40mFrontier

Tue 12/168:29 pmISP - STL

1 stop27h 04mFrontier

Deal found 12/1

$196

Fri 12/122:30 pmSTL - ISP

2 stops8h 20mSouthwest

Tue 12/165:40 amISP - STL

2 stops9h 10mSouthwest

Deal found 12/1

$505

Wed 12/173:30 pmSTL - ISP

1 stop8h 08mFrontier

Sun 12/212:04 pmISP - STL

1 stop9h 29mFrontier

Deal found 12/1

$232

Mon 12/2210:40 amSTL - ISP

1 stop8h 00mFrontier

Tue 12/3012:20 pmISP - STL

1 stop11h 13mFrontier

Deal found 12/1

$293

Mon 12/2210:40 amSTL - ISP

1 stop8h 00mFrontier

Mon 12/292:04 pmISP - STL

1 stop9h 29mFrontier

Deal found 12/1

$667

One-way flights from St. Louis to Islip
Search for one-way flight options from St. Louis to Islip. Find affordable one-way fares based on user searches. Data last updated December 3, 2025.

Wed 12/173:30 pmSTL - ISP

1 stop8h 08mFrontier

Deal found 12/1

$81

Sun 1/119:35 amSTL - ISP

1 stop9h 10mFrontier

Deal found 12/1

$122

Find flight deals from St. Louis to Islip

Most accurate provider	eDreams 3 stars
Most trusted provider	eDreams 3 stars
Round-trip from	$180 (Frontier)
One-way from	$81 (Frontier)
Popular in	March
Cheapest in	October
Average price	$358

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 December 2025

Search Deals

Fly from

Fly to

Route

Depart

Return

Price

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Fri 2/27

8:45 am-4:06 pm

1 stop6h 21m

Islip Long Island

Fri 3/6

8:19 pm-7:13 am

1 stop11h 54m

$180

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Wed 12/17

3:30 pm-12:38 am

1 stop8h 08m

Islip Long Island

Sun 12/21

2:04 pm-10:33 pm

1 stop9h 29m

$232

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Fri 2/27

10:42 am-10:40 am

2 stops22h 58m

Islip Long Island

Fri 3/6

8:19 pm-7:13 am

1 stop11h 54m

$262

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Mon 12/22

10:40 am-7:40 pm

1 stop8h 00m

Islip Long Island

Tue 12/30

12:20 pm-10:33 pm

1 stop11h 13m

$293

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Fri 2/27

5:50 am-5:00 pm

2 stops10h 10m

Islip Long Island

Fri 3/6

6:00 am-2:30 pm

2 stops9h 30m

$337

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

$667

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Wed 12/17

3:30 pm-12:38 am

1 stop8h 08m

$81

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sun 1/11

9:35 am-7:45 pm

1 stop9h 10m

$122

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/1

Compare providers for flights from St. Louis to Islip

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 December.

Provider	Price Accuracy	Trust Score*
Expedia	Price Accuracy2 stars	Trust Score*3 stars
FlightHub	Price Accuracy3 stars	Trust Score*1 star
eDreams	Price Accuracy3 stars	Trust 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?

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.

How much does it cost to fly round-trip from St. Louis to Islip, New York?

Reviews of airlines servicing Islip

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

4,253 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Southwest

8.0

Very good

4,253 reviews

Southwest

8.0

Very good

4,253 reviews

Reviews

1 / 20

2.0

Mediocre

Thomas,Dec 2025

SEA - DEN

Plane two hours late in leaving 1:00 pm west coat time got home next day at 2:45am most car rental places are closed and don’t open till 5am

Related info for your journey

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 21m. Fly via Frontier or Southwest 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 $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

Riverhead

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Top airline flying from St. Louis to Islip

Airline	Cheapest	Average	Flexibility	On-time
Southwest	Cheapest$259	Average$366	FlexibilityNo cancel fee	On-time63%

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$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 12/17. Fares are subject to change and may not be available on all flights or dates of travel.

Find cheap flights from St. Louis to Islip with Cheapflights

1. Tell us where you want to go

2. Select your favorite providers

3. Compare prices and book

Cheap flight deals from St. Louis to Islip

Cheapest flights from St. Louis to IslipExplore 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 December 3, 2025.

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 December 3, 2025.

Find flight deals from St. Louis to Islip

Most accurate provider

Most trusted provider

Round-trip from

One-way from

Popular in

Cheapest in

Average price

Cheapflights Fare Finder

Use the filters below to find and compare flights from St. Louis to Islip that are best for you.

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 December.

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.

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?

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

How much does it cost to fly round-trip from St. Louis to Islip, New York?

Reviews of airlines servicing Islip

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.

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?

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

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

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

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

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

Traveling to a place near Islip?

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Alternative routes for St. Louis to Islip

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Top airline flying from St. Louis to Islip

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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 December 3, 2025.