$109+ 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 10/5. Fares are subject to change and may not be available on all flights or dates of travel.
STL — ISP
Sep 10 — Sep 171
Round-trip
1 adult, Economy
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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
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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
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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 August 11, 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 August 11, 2026.
This Southwest deal was found by Cheapflights users on 8/10. 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 10/73:20 pm -
1 stop6h 15m
Wed 10/144:20 pm -
1 stop6h 55m
Deal found 8/10![Southwest logo]()
$214
This Southwest deal was found by Cheapflights users on 8/10. 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 10/65:30 am -
1 stop5h 40m
Tue 10/139:40 am -
2 stops6h 20m
Deal found 8/10![Southwest logo]()
$219
This Southwest deal was found by Cheapflights users on 8/8. 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.
Sat 9/52:55 pm -
1 stop4h 55m
Tue 9/83:20 pm -
1 stop6h 55m
Deal found 8/8![Southwest logo]()
$304
This Southwest deal was found by Cheapflights users on 8/9. 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.
Fri 10/165:40 pm -
1 stop4h 55m
Sun 10/186:15 pm -
1 stop6h 40m
Deal found 8/9![Southwest logo]()
$311
This Southwest deal was found by Cheapflights users on 8/7. 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.
Tue 11/1012:40 pm -
1 stop8h 00m
Thu 11/125:40 pm -
1 stop7h 25m
Deal found 8/7![Southwest logo]()
$314
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/22:29 pm -
2 stops19h 51m
Sun 10/45:43 pm -
1 stop23h 51m
Deal found 8/7![Multiple Airlines logo]()
$321
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 August 11, 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 August 11, 2026.
This Southwest deal was found by Cheapflights users on 8/10. 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 10/73:20 pm -
1 stop6h 15m
Wed 10/144:20 pm -
1 stop6h 55m
Deal found 8/10![Southwest logo]()
$214
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/22:29 pm -
2 stops19h 51m
Sun 10/45:43 pm -
1 stop23h 51m
Deal found 8/7![Multiple Airlines logo]()
$321
This Southwest deal was found by Cheapflights users on 8/10. 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 10/65:30 am -
1 stop5h 40m
Tue 10/139:40 am -
2 stops6h 20m
Deal found 8/10![Southwest logo]()
$219
This Southwest deal was found by Cheapflights users on 8/8. 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.
Sat 9/52:55 pm -
1 stop4h 55m
Tue 9/83:20 pm -
1 stop6h 55m
Deal found 8/8![Southwest logo]()
$304
This Southwest deal was found by Cheapflights users on 8/7. 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.
Tue 11/106:20 am -
2 stops8h 55m
Thu 11/125:40 pm -
1 stop7h 25m
Deal found 8/7![Southwest logo]()
$314
Last-minute flights from St. Louis to IslipDiscover last-minute flight deals from St. Louis to Islip. Data last updated August 11, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Islip. Data last updated August 11, 2026 and is based on user searches.
This Southwest deal was found by Cheapflights users on 8/10. 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 8/251:40 pm -
1 stop6h 25m
Sat 8/2911:55 am -
1 stop4h 35m
Deal found 8/10![Southwest logo]()
$421
This Southwest deal was found by Cheapflights users on 8/9. 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.
Tue 9/11:40 pm -
1 stop6h 25m
Mon 9/76:10 am -
1 stop6h 25m
Deal found 8/9![Southwest logo]()
$380
This Southwest deal was found by Cheapflights users on 8/8. 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.
Sat 9/52:55 pm -
1 stop4h 55m
Tue 9/83:20 pm -
1 stop6h 55m
Deal found 8/8![Southwest logo]()
$304
This Southwest deal was found by Cheapflights users on 8/8. 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 9/81:40 pm -
1 stop6h 30m
Tue 9/296:05 am -
1 stop5h 00m
Deal found 8/8![Southwest logo]()
$323
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 August 11, 2026.
Search for one-way flight options from St. Louis to Islip. Find affordable one-way fares based on user searches. Data last updated August 11, 2026.
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/52:29 pm -
2 stops25h 29m
Deal found 8/7![Frontier logo]()
$109
This Trip.com deal was found by Cheapflights users on 8/7. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/16:39 pm -
1 stop21h 19m
Deal found 8/7![Frontier logo]()
$115
This Frontier deal was found by Cheapflights users on 8/10. 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 10/88:34 pm -
1 stop11h 59m
Deal found 8/10![Frontier logo]()
$118
This Trip.com deal was found by Cheapflights users on 8/10. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/98:34 pm -
1 stop17h 29m
Deal found 8/10![Frontier logo]()
$121
This Southwest deal was found by Cheapflights users on 8/7. 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.
Wed 9/301:40 pm -
1 stop6h 30m
Deal found 8/7![Southwest logo]()
$155
This Frontier deal was found by Cheapflights users on 8/10. 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 10/118:34 pm -
1 stop11h 59m
Deal found 8/10![Frontier logo]()
$176
This Southwest deal was found by Cheapflights users on 8/10. 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 10/94:30 pm -
2 stops6h 05m
Deal found 8/10![Southwest logo]()
$182
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/16:39 pm -
3 stops39h 41m
Deal found 8/7![Multiple Airlines logo]()
$192
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/186:45 pm -
2 stops14h 08m
Deal found 8/7![Frontier logo]()
$330
This Kiwi.com deal was found by Cheapflights users on 8/7. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/188:00 am -
3 stops26h 17m
Deal found 8/7![Multiple Airlines logo]()
$341
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 August 11, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $214 (Southwest) |
One-way from | $109 (Kiwi.com) |
Popular in | June |
Cheapest in | February |
Average price | $349 |
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 August 11, 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
Wed 10/7
3:20 pm-10:35 pm
1 stop6h 15m
Islip Long Island
Wed 10/14
4:20 pm-10:15 pm
1 stop6h 55m
$214
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Tue 10/6
5:30 am-12:10 pm
1 stop5h 40m
Islip Long Island
Tue 10/13
9:40 am-3:00 pm
2 stops6h 20m
$219
Quickest round-trip
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Sat 9/5
2:55 pm-8:50 pm
1 stop4h 55m
Islip Long Island
Tue 9/8
3:20 pm-9:15 pm
1 stop6h 55m
$304
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Tue 11/10
6:20 am-4:15 pm
2 stops8h 55m
Islip Long Island
Thu 11/12
5:40 pm-12:05 am
1 stop7h 25m
$314
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Fri 10/2
2:29 pm-11:20 am
2 stops19h 51m
Islip Long Island
Sun 10/4
5:43 pm-4:34 pm
1 stop23h 51m
$321
Cheapest one-way
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Mon 10/5
5:19 pm-4:58 pm
1 stop22h 39m
$115
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Thu 10/8
8:34 pm-9:33 am
1 stop11h 59m
$118
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Sat 10/10
8:34 pm-9:33 am
1 stop11h 59m
$118
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Wed 9/30
1:40 pm-9:10 pm
1 stop6h 30m
$155
St. LouisIslip
STL Lambert-St Louis - ISP Islip Long Island
STLISP
Lambert-St Louis
Thu 10/1
5:25 am-2:30 pm
2 stops8h 05m
$160
Showing 1-10 of 14 resultsSorted 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 August.
| 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 August 11, 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.
Crew
8.6
Boarding
8.1
Overall
8.0
Food
7.0
Entertainment
7.5
Comfort
8.0
Reviews
1 / 20
2.0
MediocreBhoopal,Nov 2024
STL - BOS
Crew
8.6
Boarding
8.1
Overall
8.0
Food
7.0
Entertainment
7.5
Comfort
8.0
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
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St. Louis and Islip flights
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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 August 11, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$218 | Average$376 | FlexibilityNo cancel fee | On-time63% |