STL - ISP

$84 Find Cheap Flights from St. Louis to Islip

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from St. Louis to Islip departing on 10/23. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy

KAYAK searches hundreds of travel sites at once for deals on flights to Islip

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to Islip, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from St. Louis to Islip, as well as popular online travel agencies
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Flight Deals

Cheap Flights from St. Louis to Islip (STL-ISP)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from St. Louis to Islip that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from St. Louis to Islip

Thu, Sep 25 - Mon, Sep 29
Frontier Logo
10:49 am - 10:40 amSTL-ISP
22h 51m2 stops
Frontier Logo
5:05 pm - 9:06 amISP-STL
17h 01m2 stops
$238Frontier
Find Deal
Sat, Sep 27 - Mon, Sep 29
Frontier Logo
7:55 pm - 9:04 amSTL-ISP
12h 09m2 stops
Frontier Logo
5:05 pm - 9:06 amISP-STL
17h 01m2 stops
$245Frontier
Find Deal
Tue, Oct 28 - Thu, Oct 30
Frontier Logo
8:40 pm - 10:37 amSTL-ISP
12h 57m2 stops
Frontier Logo
6:37 pm - 3:57 pmISP-STL
22h 20m2 stops
$346Frontier
Find Deal
Mon, Sep 29 - Sun, Oct 5
Southwest Logo
9:05 am - 4:30 pmSTL-ISP
6h 25m1 stop
Southwest Logo
5:25 am - 2:30 pmISP-STL
10h 05m2 stops
$512Southwest
Find Deal
Mon, Sep 29 - Sun, Oct 5
Southwest Logo
5:25 am - 12:00 pmSTL-ISP
5h 35m2 stops
Southwest Logo
5:25 am - 2:30 pmISP-STL
10h 05m2 stops
$553Southwest
Find Deal
Sun, Nov 23 - Sat, Nov 29
Frontier Logo
10:24 am - 6:53 pmSTL-ISP
7h 29m1 stop
Frontier Logo
6:00 am - 4:53 pmISP-STL
11h 53m1 stop
$920Frontier
Find Deal

Everything you should know

Top airlines
Frontier
Cheapest • from $238 (round-trip)
Southwest
Best reviews • 8.0 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Cheapest round-trip
$238
Frontier
Thu 9/25Mon 9/29
STL - ISP • 2 stops
Cheapest one-way
$84
Frontier
Thu 10/23
STL - ISP • 1 stop
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KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to Islip!
Booking Insights

KAYAK's insights & trends for St. Louis to Islip flights

Get data-powered insights and trends into flights from St. Louis to Islip to help you find the cheapest flights, the best time to fly and much more.

Which airlines provide the cheapest flights from St. Louis to Islip?

The cheapest round-trip price for the route for each airline clicked by KAYAK users in the last 72 hours.

In the past 3 days, the cheapest round-trip tickets from St. Louis to Islip were found on Frontier ($238) and Southwest ($512).

Find deals

Good to know

Low seasonApril
Cheapest flight$84
Best time to beat the crowds with an average 26% drop in price.
Most popular time to fly and prices are also 1% lower on average.
Flight from St. Louis to Islip

When to book flights from St. Louis to Islip

Are your dates flexible? Find out the best times to travel from St. Louis to Islip based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from St. Louis to Islip

  • What is the cheapest flight from St. Louis to Islip?

    In the last 3 days, the lowest price for a flight from St. Louis to Islip was $84 for a one-way ticket and $238 for a round-trip.

  • Do I need a passport to fly between St. Louis and Islip?

    No, a passport isn't needed to fly from St. Louis to Islip. However, local authorities might ask for an official ID.

  • Which airports will I be using when flying from St. Louis to Islip?

    When flying out of St. Louis you will be using Lambert-St Louis. You will be landing at Islip, also known as Islip Long Island.

  • Which aircraft models fly most regularly from St. Louis to Islip?

    We unfortunately don’t have that data for this specific route.

  • How does KAYAK find such low prices on flights from St. Louis to Islip?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from St. Louis to Islip.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from St. Louis to Islip?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to Islip from St. Louis is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from St. Louis to Islip?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to Islip with an airline and back to St. Louis with another airline. Booking your flights between St. Louis and ISP can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from St. Louis to Islip?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to Islip from St. Louis up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

Reviews of the top airline flying from St. Louis to Islip

 
See real verified KAYAK customer reviews for airlines flying from St. Louis to Islip. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from St. Louis to Islip? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4248 reviews
8.1Boarding
7.5Entertainment
8.0Comfort
7.0Food
8.6Crew
Airline reviews

I wish they had movie screens in the headrests. The seats are much improved, more legroom and recently renovated. Bathroom was clean. Staff was outstanding!!

10.0 ExcellentG, Sep 2025LAS - ATL
Read more Southwest reviews

I wish they had movie screens in the headrests. The seats are much improved, more legroom and recently renovated. Bathroom was clean. Staff was outstanding!!

As always, the entire Southwest experience was wonderful, from online booking to flight to baggage retrieval. Very grateful.

The weather could have been better. There was a 40 minute ATC delay in SFO because of marine fog and a micro cell storm delayed landing and take-off at Nashville. The gate was changed 5 minutes from boarding from gate B3 to gate C23 at Nashville airport.

After being assaulted by a flight attendant I was then brushed off as oh well because he long braids didn’t mean to whip me in the eye. I have filed complaints and will see. But like any other issue I’ve had with kayak involved it’s been trash. Last time I’ll be using your app

AC sub par. WiFi not working correctly. Ac sucked. Seats very narrow.

Near 4 hour flight with only 1 service. Had to use call button to request water. Internet and power not working until into flight. Internet would stop working during flight.

Southwest's seats are the least comfortable I have ever sat in.

The cabin was quiet for the redeye flight. The area was clean. The staff was great. The 787 Max was in good condition. Drawbacks were that the seat widths were tight for some passengers. The seat padding was at best average and for a long flight uncomfortable.

Southwest like most American domestic airlines, is a mediocre airline. But it is among the cheapest. Oh well.

My flight was delayed 50 minutes and we were rushed to board to then sit for 15 minutes until the pilot arrived. Unacceptable since we could have waited to board. Also the delayed flight was updated AFTER we boarded to more than the 10 minutes as originally stated.

Everything you need to know for your flight from St. Louis to Islip

Information on your arrival and departure airports

St. Louis (STL)
Islip (ISP)

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