STL - ISP

$137 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 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

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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Flights 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

Sun, Aug 3 - Sat, Aug 9
Frontier Logo
5:40 pm - 7:52 pmSTL-ISP
25h 12m1 stop
Frontier Logo
8:37 pm - 11:47 pmISP-STL
28h 10m1 stop
$333Frontier
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Sun, Aug 3 - Sat, Aug 9
Southwest Logo
5:20 pm - 11:55 pmSTL-ISP
5h 35m1 stop
Southwest Logo
5:40 am - 2:15 pmISP-STL
9h 35m2 stops
$372Southwest
Find Deal
Sun, Aug 3 - Sat, Aug 9
Frontier Logo
2:36 pm - 11:47 pmSTL-ISP
8h 11m2 stops
Frontier Logo
8:37 pm - 1:34 pmISP-STL
17h 57m2 stops
$393Frontier
Find Deal
Useful Info

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 ($333) and Southwest ($372).

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Good to know

Low seasonApril
High seasonJune
Cheapest flight$137
Best time to beat the crowds with an average 21% drop in price.
Most popular time to fly with an average 6% increase in price.
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 $137 for a one-way ticket and $333 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 4266 reviews
8.6Crew
7.6Entertainment
8.2Boarding
7.0Food
8.0Comfort
Airline reviews

Delayed flight. Nicest crew member was a SW pilot flying seated next to me who kindly move to seat the final passenger. Flight extra delayed. My cup of refreshment of ginger ale was so packed with ice it was literally 2 sips.

4.0 OkayTraci, Jun 2025OAK - SEA
Read more Southwest reviews

Delayed flight. Nicest crew member was a SW pilot flying seated next to me who kindly move to seat the final passenger. Flight extra delayed. My cup of refreshment of ginger ale was so packed with ice it was literally 2 sips.

For my birthday trip this was my second time ever flying, this trip was the best.

after landing, we stay 2 hours on the taxi way before reaching the gate The airline and the crew were good though

No trays in our seats, we sat in first row, purchased a business class fare. Had to hold our drinks and snack in our hands. No plugs for our cell phones. Had to pay for it a drink cocktail each. Seats so uncomfortable.

Flight wasn’t even full, but too many carry-ons caused us to run out of bin space. New bag fee has folks who would usually check their bags carrying on. Watching Southwest morph into Spirit/Frontier is so sad to watch

Sat on tarmac for 2 hours and then missed my connecting flight

First time traveling on Southwest since bag fees were implemented. Usual good service. Just more expensive now.

Everything was on time. I was disappointed by the front section female, African American flight attendant. I did not see her name tag or would have identified by name not race. As passengers moved to the bathroom early in flight, she would say with a disdainful tone “I have to say the seat belt light is on” then go back to her book. Better trained flight attendants say something like be careful the seat belt light is on.

Cluster mess boarding. Can't wait for SWA reserved seating. Internet didn't seem to work on the plane.

Flights delayed by 4-6 hours. Boarding was a mess and unclear. Bags were not at arrival airport and had never even been put on the plane. No idea when I’ll get them. Don’t fly into Denver!

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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