STL - ISP

$114 Find Cheap Flights from St. Louis to Islip - Compare and Save

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 9/7. 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

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Everything you should know

Cheapest round-trip
$176
Frontier
Mon 8/31Wed 9/9
STL - ISP • 1 stop
Cheapest one-way
$114
Frontier
Mon 9/7
STL - ISP • 1 stop
Top airlines
Frontier
Cheapest • from $176 (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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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

Mon, Aug 31 - Wed, Sep 9
Frontier Logo
4:23 pm - 9:53 am
STL
-
ISP
16h 30m
1 stop
Frontier Logo
5:43 pm - 5:54 pm
ISP
-
STL
25h 11m
1 stop
$176Frontier
Wed, Oct 7 - Wed, Oct 14
Southwest Logo
3:20 pm - 10:35 pm
STL
-
ISP
6h 15m
1 stop
Southwest Logo
6:05 am - 11:35 am
ISP
-
STL
6h 30m
1 stop
$255Southwest
Thu, Sep 10 - Mon, Sep 14
Southwest Logo
12:55 pm - 9:35 pm
STL
-
ISP
7h 40m
1 stop
Southwest Logo
5:00 pm - 10:30 pm
ISP
-
STL
6h 30m
1 stop
$255Southwest
Wed, Oct 7 - Wed, Oct 14
Southwest Logo
3:20 pm - 10:35 pm
STL
-
ISP
6h 15m
1 stop
Southwest Logo
12:50 pm - 7:20 pm
ISP
-
STL
7h 30m
1 stop
$255Southwest
Thu, Aug 27 - Sat, Aug 29
Frontier Logo
5:02 pm - 9:53 am
STL
-
ISP
15h 51m
1 stop
Frontier Logo
10:57 am - 4:11 pm
ISP
-
STL
6h 14m
1 stop
$256Frontier
Thu, Sep 10 - Mon, Sep 14
Southwest Logo
2:25 pm - 9:35 pm
STL
-
ISP
6h 10m
1 stop
Southwest Logo
4:05 pm - 10:10 pm
ISP
-
STL
7h 05m
2 stops
$260Southwest
Wed, Oct 7 - Wed, Oct 14
Southwest Logo
5:25 am - 1:10 pm
STL
-
ISP
6h 45m
1 stop
Southwest Logo
12:50 pm - 7:00 pm
ISP
-
STL
7h 10m
2 stops
$260Southwest
Wed, Oct 7 - Wed, Oct 14
Southwest Logo
5:25 am - 3:30 pm
STL
-
ISP
9h 05m
2 stops
Southwest Logo
12:50 pm - 7:20 pm
ISP
-
STL
7h 30m
1 stop
$260Southwest
Thu, Sep 10 - Mon, Sep 14
Southwest Logo
11:40 am - 9:35 pm
STL
-
ISP
8h 55m
2 stops
Southwest Logo
4:05 pm - 10:10 pm
ISP
-
STL
7h 05m
2 stops
$265Southwest
Wed, Oct 7 - Wed, Oct 14
Southwest Logo
8:30 am - 3:45 pm
STL
-
ISP
6h 15m
2 stops
Southwest Logo
12:50 pm - 7:00 pm
ISP
-
STL
7h 10m
2 stops
$265Southwest
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 5 days.

In the past 5 days, the cheapest round-trip tickets from St. Louis to Islip were found on Frontier ($176) and Southwest ($255).

Find deals

Good to know

Cheapest flight

$114
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 5 days, the lowest price for a flight from St. Louis to Islip was $114 for a one-way ticket and $176 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 4229 reviews
8.6Crew
8.1Boarding
8.0Comfort
7.5Entertainment
7.0Food
Airline reviews

The flight was delayed due to earlier issues at other airports. The crew was excellent & made it a good trip.

6.0 GoodJeremy, Aug 2026
STL - PHL
Read more Southwest reviews

The flight was delayed due to earlier issues at other airports. The crew was excellent & made it a good trip.

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

Only downside was the legroom and seat width, which is always a problem unless I spend more for a premium seat.

Very good. Sad to learn Southwest is going start to charge for bags

Exceptional crew! Friendly and professional. Pleasant attitude and treated everyone with respect.

The flight was promptly on schedule and Southwest delivered everything they promised. No excuses for any shortfalls just 100% ownership of their responsibilities and business. The boarding and seating policy is a complete shambles. What started out as a great idea when Southwest first hit the market has been turned into a disaster due to the lack of integrity in many of the people who fly Southwest and take advantage of Southwest generosity at the expense of their fellow passengers.

Crew was excellent - Plane was fine. Media was good, could use more kid shows; Not a fan of the brownie brittle -- snack could be slightly better.

Left on time and arrived early. Brand new plane and no parts missing. Comfortable seats. The actual Captain spoke prior to the flight and reassured everyone about safety. Crew was so nice and fun. Perfect flight!

Everything went smoothly and the plane wasn’t full. It was delayed though. The delay was increased due to a crew change which was frustrating.

Love Southwest! Always a good trip with a happy crew who goes out of their way to be kind and fun.

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)