STL - ISP

$161 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 4/2. 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, 0 bags

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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41 299 237 searches in the past 7 days on KAYAK

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Everything you should know

Cheapest round-trip
$236
Frontier
Fri 4/3Tue 4/7
STL - ISP • 1 stop
Cheapest one-way
$161
Frontier
Thu 4/2
STL - ISP • 1 stop
Top airlines
Frontier
Cheapest • from $236 (round-trip)
Southwest
Best reviews • 8.0 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Nonstop flights
Not available
There are currently no direct flights between St. Louis and Islip. You'll need at least 1 connection.
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We hope you love your trip to Islip!
Flight Deals
Booking Insights
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

Fri, Apr 3 - Tue, Apr 7
Frontier Logo
8:23 am - 5:55 pm
STL
-
ISP
8h 32m
1 stop
Frontier Logo
5:43 pm - 11:25 pm
ISP
-
STL
6h 42m
1 stop
$236Frontier
Fri, Apr 3 - Wed, Apr 8
Frontier Logo
8:23 am - 5:55 pm
STL
-
ISP
8h 32m
1 stop
Frontier Logo
5:28 pm - 11:25 pm
ISP
-
STL
6h 57m
1 stop
$315Frontier
Fri, May 1 - Fri, May 8
Southwest Logo
5:00 am - 4:30 pm
STL
-
ISP
10h 30m
1 stop
Southwest Logo
5:10 pm - 11:40 pm
ISP
-
STL
7h 30m
1 stop
$318Southwest
Fri, May 1 - Fri, May 8
Southwest Logo
2:25 pm - 11:30 pm
STL
-
ISP
8h 05m
2 stops
Southwest Logo
4:30 pm - 11:15 pm
ISP
-
STL
7h 45m
2 stops
$323Southwest
Fri, Apr 3 - Sun, Apr 5
Frontier Logo
8:23 am - 5:55 pm
STL
-
ISP
8h 32m
1 stop
Frontier Logo
7:59 pm - 7:51 am
ISP
-
STL
12h 52m
1 stop
$325Frontier
Fri, Apr 3 - Sun, Apr 5
Frontier Logo
8:23 am - 5:55 pm
STL
-
ISP
8h 32m
1 stop
Frontier Logo
7:59 pm - 7:51 am
ISP
-
STL
12h 52m
1 stop
$335Frontier
Fri, Apr 3 - Sat, Apr 4
Frontier Logo
8:23 am - 5:55 pm
STL
-
ISP
8h 32m
1 stop
Frontier Logo
11:15 am - 11:25 pm
ISP
-
STL
13h 10m
1 stop
$395Frontier
Mon, Mar 30 - Fri, Apr 3
Southwest Logo
4:45 pm - 11:55 pm
STL
-
ISP
6h 10m
1 stop
Southwest Logo
2:00 pm - 5:50 pm
ISP
-
STL
4h 50m
1 stop
$477Southwest
Mon, Mar 30 - Fri, Apr 3
Southwest Logo
4:25 pm - 11:55 pm
STL
-
ISP
6h 30m
2 stops
Southwest Logo
2:00 pm - 5:50 pm
ISP
-
STL
4h 50m
1 stop
$482Southwest
Mon, Mar 30 - Fri, Apr 3
Southwest Logo
4:55 pm - 11:55 pm
STL
-
ISP
6h 00m
2 stops
Southwest Logo
5:55 pm - 12:05 am
ISP
-
STL
7h 10m
2 stops
$503Southwest
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 ($236) and Southwest ($318).

Find deals

Good to know

Cheapest flight$161
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 $161 for a one-way ticket and $236 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 4320 reviews
8.1Boarding
8.6Crew
7.5Entertainment
7.0Food
8.0Comfort
Airline reviews

We had a 5 hour delay on the tarmac in Baltimore

2.0 MediocreDavid, Mar 2026
ALB - BWI
Read more Southwest reviews

We had a 5 hour delay on the tarmac in Baltimore

Long layover between flights to Long Island from BWI - need better coordination between flights

I elected to pay for the upgrades and found very little difference

The new seating arrangement is so over priced for what you get.

The problem with the seat assignments is that there were a lot of rows in the front that were empty but my row at the back was full. Just not so pleasant.

No food or entertainment, just a quick 40 minute flight. A little bumpy due to Santa Ana winds but pilot has no control over that. Good flight and landing!

Good but I prefer choose your own seat. With the new assigned seats they should board from the back I see no advantage to this new boarding. Just like every other airline

I realize they are still working out kinks with the new boarding process, but by the time I boarded in group 5, most of the bins were full. All airlines should better enforce small bags and jackets going under the seats until everyone has boarded.

WiFi was not working and didn’t have a beverage service

Snacks are always pretzels. Why can't you also offer peanuts ?

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)