HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Islip

$115+ 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 1/16. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ISP
Jan 27 — Feb 31
Tue 1/27
Tue 2/3
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

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 28, 2025.

This Frontier deal was found by Cheapflights users on 12/25. 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.
Mon 1/128:50 amSTL - ISP
1 stop10h 01mFrontier
Thu 1/159:52 amISP - STL
1 stop13h 42mFrontier
Deal found 12/25$162
This Kiwi.com deal was found by Cheapflights users on 12/27. 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.
Sun 1/115:11 pmSTL - ISP
1 stop25h 40mMultiple Airlines
Thu 1/1511:55 amISP - STL
2 stops11h 39mMultiple Airlines
Deal found 12/27$295
This Kiwi.com deal was found by Cheapflights users on 12/26. 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.
Sat 1/105:11 pmSTL - ISP
1 stop25h 34mFrontier
Wed 1/148:00 amISP - STL
2 stops47h 51mFrontier
Deal found 12/26$394
This Frontier deal was found by Cheapflights users on 12/27. 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.
Sun 1/119:35 amSTL - ISP
1 stop9h 10mFrontier
Thu 1/157:58 pmISP - STL
1 stop12h 56mFrontier
Deal found 12/27$520
This Cheapflightsfares deal was found by Cheapflights users on 12/27. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 3/197:52 amSTL - ISP
1 stop6h 57mFrontier
Sun 3/224:34 pmISP - STL
1 stop7h 45mFrontier
Deal found 12/27$889

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 December 28, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$162
(Frontier)

One-way from

$115
(Cheapflightsfares)

Popular in

March

Cheapest in

October

Average price

$321
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. 7% potential increase in price ($27 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 5% potential price decrease ($19 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 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 December 28, 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

Mon 1/12

8:50 am-7:51 pm

1 stop10h 01m

Islip Long Island

Thu 1/15

9:52 am-10:34 pm

1 stop13h 42m

$162

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sun 1/11

5:11 pm-7:51 pm

1 stop25h 40m

Islip Long Island

Thu 1/15

11:55 am-10:34 pm

2 stops11h 39m

$295

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sat 1/10

5:11 pm-7:45 pm

1 stop25h 34m

Islip Long Island

Wed 1/14

8:00 am-6:51 am

2 stops47h 51m

$394

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Sun 1/11

9:35 am-7:45 pm

1 stop9h 10m

Islip Long Island

Thu 1/15

7:58 pm-7:54 am

1 stop12h 56m

$520

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 3/19

7:52 am-3:49 pm

1 stop6h 57m

Islip Long Island

Sun 3/22

4:34 pm-11:19 pm

1 stop7h 45m

$889

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Fri 1/16

12:47 pm-7:50 pm

1 stop6h 03m

$115

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Mon 1/19

12:47 pm-7:50 pm

1 stop6h 03m

$150

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 1/15

5:11 pm-8:09 pm

1 stop25h 58m

$191

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 3/19

7:52 am-3:49 pm

1 stop6h 57m

$240

St. LouisIslip

STL - ISP

STLISP

Lambert-St Louis

Thu 1/15

5:11 pm-1:21 pm

2 stops19h 10m

$266

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/26

Showing 1-10 of 13 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 December.
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, January 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.

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 December 28, 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
4,256 reviews

Entertainment

7.5

Crew

8.6

Overall

8.0

Comfort

8.0

Boarding

8.1

Food

7.0

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
4,256 reviews
Southwest
8.0
Very good
4,256 reviews

Entertainment

7.5

Crew

8.6

Overall

8.0

Comfort

8.0

Boarding

8.1

Food

7.0

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

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 10h 01m. 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 28% 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 $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

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 Newark flights
St. Louis to LaGuardia flights
Kansas City to LaGuardia flights
Kansas City to John F Kennedy Intl flights
St. Louis to John F Kennedy Intl flights
Kansas City to Newark flights
Springfield to John F Kennedy Intl flights
Springfield to Newark flights
Springfield to LaGuardia flights
St. Louis to Buffalo flights
Kansas City to Buffalo flights
St. Louis to Albany flights
Columbia to LaGuardia flights
Kansas City to Rochester flights
Kansas City to Syracuse flights
Columbia to Newark flights
Springfield to Buffalo flights
Kansas City to Ithaca flights
Columbia to John F Kennedy Intl flights
Joplin to Newark flights
Joplin to LaGuardia flights
Kansas City to Elmira flights
St. Louis to Rochester flights
St. Louis to Syracuse flights
Kansas City to Albany flights
St. Louis to White Plains flights
Springfield to Syracuse flights
Kansas City to Stewart flights
Columbia to Rochester flights
Kansas City to White Plains flights
Columbia to Albany flights
St. Louis to Ithaca flights
Springfield to White Plains flights
St. Louis to Stewart flights
St. Louis to Elmira flights
Springfield to Albany flights
Columbia to Syracuse flights
Columbia to Buffalo flights
Kansas City to Binghamton flights
Joplin to Syracuse flights
St. Louis to Watertown flights
Springfield to Stewart flights
Springfield to Islip flights
Kansas City to Plattsburgh flights
Kansas City to Islip flights
Kansas City to Watertown flights
Joplin to John F Kennedy Intl 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 December 28, 2025.
AirlineCheapestAverageFlexibilityOn-time
SouthwestCheapest$259Average$366FlexibilityNo 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.