$254+ Cheap flights from St. Louis to Islip, NY (STL - ISP)
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 11/3. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ISP
Nov 8 — Nov 151
Round-trip
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
Cheapest
Best
Last-minute
One-way
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 October 9, 2026.
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 October 9, 2026.
This Southwest deal was found by Cheapflights users on 10/6. 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 11/312:35 pm -
1 stop7h 30m
Tue 11/1012:30 pm -
1 stop6h 35m
Deal found 10/6![Southwest logo]()
$254
This Southwest deal was found by Cheapflights users on 10/4. 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.
Fri 11/65:10 pm -
1 stop5h 25m
Sun 11/84:25 pm -
1 stop8h 45m
Deal found 10/4![Southwest logo]()
$376
This Southwest deal was found by Cheapflights users on 10/6. 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.
Fri 12/184:25 pm -
2 stops6h 20m
Sun 12/206:00 pm -
1 stop6h 55m
Deal found 10/6![Southwest logo]()
$383
This Southwest deal was found by Cheapflights users on 10/8. 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.
Wed 11/253:30 pm -
1 stop7h 10m
Mon 11/306:00 pm -
1 stop6h 55m
Deal found 10/8![Southwest logo]()
$487
This Mytrip deal was found by Cheapflights users on 10/4. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/66:34 pm -
2 stops21h 57m
Sun 11/86:33 pm -
3 stops43h 48m
Deal found 10/4![Multiple Airlines logo]()
$496
Best flights from St. Louis to IslipDiscover 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 October 9, 2026.
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 October 9, 2026.
This Southwest deal was found by Cheapflights users on 10/4. 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.
Fri 11/64:40 pm -
2 stops5h 55m
Sun 11/84:25 pm -
1 stop8h 45m
Deal found 10/4![Southwest logo]()
$381
This Mytrip deal was found by Cheapflights users on 10/4. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/66:34 pm -
2 stops21h 57m
Sun 11/86:33 pm -
3 stops43h 48m
Deal found 10/4![Multiple Airlines logo]()
$496
This Southwest deal was found by Cheapflights users on 10/6. 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.
Fri 12/184:25 pm -
2 stops6h 20m
Sun 12/206:00 pm -
1 stop6h 55m
Deal found 10/6![Southwest logo]()
$383
This Southwest deal was found by Cheapflights users on 10/6. 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.
Mon 3/155:05 am -
1 stop6h 25m
Thu 3/185:20 pm -
1 stop6h 45m
Deal found 10/6![Southwest logo]()
$450
This Southwest deal was found by Cheapflights users on 10/6. 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.
Mon 11/238:20 pm -
1 stop11h 25m
Wed 11/259:25 am -
1 stop9h 10m
Deal found 10/6![Southwest logo]()
$532
This Southwest deal was found by Cheapflights users on 10/8. 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 11/248:00 pm -
1 stop11h 45m
Sun 11/295:25 am -
1 stop5h 15m
Deal found 10/8![Southwest logo]()
$582
This Southwest deal was found by Cheapflights users on 10/8. 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.
Wed 11/253:30 pm -
1 stop7h 10m
Sun 11/295:25 am -
1 stop5h 15m
Deal found 10/8![Southwest logo]()
$667
Last-minute flights from St. Louis to IslipDiscover last-minute flight deals from St. Louis to Islip. Data last updated October 9, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Islip. Data last updated October 9, 2026 and is based on user searches.
This Southwest deal was found by Cheapflights users on 10/6. 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 11/312:35 pm -
1 stop7h 30m
Tue 11/1012:30 pm -
1 stop6h 35m
Deal found 10/6![Southwest logo]()
$254
This Southwest deal was found by Cheapflights users on 10/4. 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.
Fri 11/65:10 pm -
1 stop5h 25m
Sun 11/84:25 pm -
1 stop8h 45m
Deal found 10/4![Southwest logo]()
$376
This Mytrip deal was found by Cheapflights users on 10/4. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/66:34 pm -
2 stops21h 57m
Sun 11/86:33 pm -
3 stops43h 48m
Deal found 10/4![Multiple Airlines logo]()
$496
This Southwest deal was found by Cheapflights users on 10/6. 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.
Mon 11/238:20 pm -
1 stop11h 25m
Wed 11/259:25 am -
1 stop9h 10m
Deal found 10/6![Southwest logo]()
$532
This Southwest deal was found by Cheapflights users on 10/8. 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.
Wed 11/253:30 pm -
1 stop7h 10m
Mon 11/306:00 pm -
1 stop6h 55m
Deal found 10/8![Southwest logo]()
$487
One-way flights from St. Louis to IslipSearch for one-way flight options from St. Louis to Islip. Find affordable one-way fares based on user searches. Data last updated October 9, 2026.
Search for one-way flight options from St. Louis to Islip. Find affordable one-way fares based on user searches. Data last updated October 9, 2026.
This Frontier deal was found by Cheapflights users on 10/5. 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 11/273:04 pm -
2 stops23h 41m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 10/5![Frontier logo]()
$518
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 October 9, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $254 (Southwest) |
Popular in | September |
Cheapest in | February |
Average price | $382 |
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 7,457,451 searches. Data last updated October 9, 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
Cheapest round-trip
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Fri 11/6
4:40 pm-11:35 pm
2 stops5h 55m
Islip Long Island
Sun 11/8
4:25 pm-12:10 am
1 stop8h 45m
$381
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Fri 12/18
4:25 pm-11:45 pm
2 stops6h 20m
Islip Long Island
Sun 12/20
6:00 pm-11:55 pm
1 stop6h 55m
$383
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Mon 3/15
5:05 am-12:30 pm
1 stop6h 25m
Islip Long Island
Thu 3/18
5:20 pm-11:05 pm
1 stop6h 45m
$450
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Fri 11/6
6:34 pm-5:31 pm
2 stops21h 57m
Islip Long Island
Sun 11/8
6:33 pm-1:21 pm
3 stops43h 48m
$496
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Fri 11/27
3:04 pm-3:45 pm
2 stops23h 41m
Islip Long Island
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$518
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Mon 11/23
8:20 pm-8:45 am
1 stop11h 25m
Islip Long Island
Wed 11/25
9:25 am-5:35 pm
1 stop9h 10m
$532
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Tue 11/24
8:00 pm-8:45 am
1 stop11h 45m
Islip Long Island
Sun 11/29
5:25 am-9:40 am
1 stop5h 15m
$582
Quickest round-trip
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Wed 11/25
3:30 pm-11:40 pm
1 stop7h 10m
Islip Long Island
Sun 11/29
5:25 am-9:40 am
1 stop5h 15m
$667
Sorted by cheapest first
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 October.
| Provider | Price Accuracy | Trust Score* |
|---|---|---|
| Price Accuracy1 star | Trust Score*3 stars | |
| Price Accuracy3 stars | Trust Score*3 stars |
- 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.
STL-ISP
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.
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 October 9, 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.
Entertainment
7.4
Crew
8.6
Comfort
8.0
Food
7.0
Overall
7.9
Boarding
8.1
Reviews
1 / 20
2.0
MediocreBhoopal,Nov 2024
STL - BOS
Entertainment
7.4
Crew
8.6
Comfort
8.0
Food
7.0
Overall
7.9
Boarding
8.1
Reviews
1 / 20
2.0
MediocreBhoopal,Nov 2024
STL - BOS
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.
Traveling to a place near Islip?
Book flights to Islip if you plan to visit one of these locationsRiverhead
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
Complete your trip
Flights by cabin class
Islip flight routes
Other flight options
Other flights from St. Louis
Popular flights
Alternative routes for St. Louis to Islip
See prices for flight routes from nearby airports that may be better suited for you.
Complete your trip
Complete your trip to Islip by adding a car rental and/or hotel reservation to your travel itinerary.
Search flights from St. Louis to Islip by cabin class
Find flights from St. Louis to Islip, based on your preferred cabin class, be it economy, premium economy, business, or first class.
Other flights to Islip
Explore flights to Islip departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on October 9, 2026.
St. Louis and Islip flights
Browse other St. Louis and Islip flight options. Last updated on October 9, 2026.
Other flights from St. Louis
Browse through other flights departing from St. Louis. Flights are based on user searches made on Cheapflights and were last updated on October 9, 2026.
Popular flight searches
Check out other popular destinations found by fellow travelers in 2026
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 7,457,451 searches. Data last updated October 9, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$218 | Average$337 | FlexibilityNo cancel fee | On-time63% |