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Use the filters below to find and compare flights from Islip, New York to St. Louis that are best for you.
Fly from
Fly to
Route
Depart
Return
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Wed 10/21
4:20 pm-10:30 pm
1 stop7h 10m
Lambert-St Louis
Mon 10/26
5:40 pm-11:40 pm
1 stop5h 00m
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Wed 10/21
4:20 pm-10:30 pm
1 stop7h 10m
Lambert-St Louis
Mon 10/26
2:30 pm-11:15 pm
2 stops7h 45m
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Wed 10/21
9:40 am-4:45 pm
2 stops8h 05m
Lambert-St Louis
Mon 10/26
5:40 pm-11:40 pm
1 stop5h 00m
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Wed 10/21
9:40 am-3:00 pm
2 stops6h 20m
Lambert-St Louis
Mon 10/26
2:30 pm-11:15 pm
2 stops7h 45m
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Thu 10/22
5:40 pm-11:20 pm
1 stop6h 40m
Lambert-St Louis
Mon 10/26
4:05 pm-11:15 pm
1 stop6h 10m
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Tue 10/20
12:50 pm-7:20 pm
1 stop7h 30m
Lambert-St Louis
Sat 10/24
1:20 pm-8:10 pm
1 stop5h 50m
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Wed 10/21
9:40 am-3:00 pm
2 stops6h 20m
Lambert-St Louis
Mon 10/26
2:30 pm-11:15 pm
2 stops7h 45m
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Tue 11/24
4:40 pm-1:21 pm
3 stops21h 41m
Lambert-St Louis
Sat 11/28
3:04 pm-3:45 pm
2 stops23h 41m
IslipSt. Louis
ISP Islip Long Island - STL Lambert-St Louis
ISPSTL
Islip Long Island
Sun 11/29
4:40 pm-11:59 pm
1 stop8h 19m
See travel insights to St. Louis from
How to get the cheapest flight ticket from Islip, New York to St. Louis
Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip
What is the cheapest day to depart on your flight to St. Louis?
The cheapest day to depart on your flight to St. Louis is on a Wednesday when prices can be found for as low as $393. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Monday because tickets tend to average around $506. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.
What is the cheapest time of day to depart on your flight to St. Louis?
Flying to St. Louis from Islip, New York in the evening is the least expensive time of day to depart. momondo users have found prices as low as $411 when looking at flights departing in the evening. At noon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $445 per ticket.
What is the cheapest airline that flies from Islip Long Island to Lambert-St Louis?
Frontier is the most popular carrier operating from Islip Long Island to Lambert-St Louis
What airlines fly to St. Louis?
United Airlines, Delta and Southwest are the top three most popular airlines that fly to St. Louis from Islip, New York according to our data. United Airlines is the first choice among our users, with 49% of people opting to fly with this airline when traveling to St. Louis. Keep in mind that there are 5 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.
When to book flights from Islip, New York to St. Louis
Cheap Islip, New York to St. Louis (ISP to STL) flight deals and tips
Find info about flight duration, direct flights, and airports for your flight from Islip, New York to St. Louis
Frequently asked questions about flying from Islip, New York to St. Louis
How far is Islip Long Island to Lambert-St Louis by plane?
There are 912.8 mi between Islip Long Island and Lambert-St Louis. In terms of flight time, this usually takes a little over 6h 40m.
When did momondo last update prices for flights from Islip Long Island Airport to Lambert-St Louis Airport?
Prices for flights from Islip Long Island Airport to Lambert-St Louis Airport are refreshed on a daily basis.
How many operators does momondo search for flights from Islip Long Island Airport to Lambert-St Louis Airport?
As of October 2026, there is 1 operator available to choose from for flights from Islip Long Island Airport to Lambert-St Louis Airport.
How old do you have to be to fly from Islip Long Island Airport to Lambert-St Louis Airport?
The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Islip Long Island Airport to Lambert-St Louis Airport.
What documentation or ID do you need to fly to Lambert-St Louis Airport?
The travel and health documents you'll need for your trip to Lambert-St Louis Airport may differ based on your itinerary and personal situation. Typically, you should have several documents on hand, such as a national ID card or driver's license and a passport that is valid for six months after your intended arrival at Lambert-St Louis Airport. It is always advisable to seek advice from your airline or a trusted third party, such as IATA.
What is the most popular airline from Islip, New York to St. Louis?
Based on momondo bookings for flights between Islip, New York and St. Louis, the leading airline is Southwest, making up 100% of the total bookings.
Best airlines flying from Islip, New York to St. Louis
Compare and see reviews for airlines that fly from Islip, New York to St. Louis with momondo
| Airline | Rating | Free Cancellation | Price | ||
|---|---|---|---|---|---|
| PriceFrom $214 | Free Cancellation | Rating 7.9 4,219 reviews |
Traveling to a place near St. Louis?
Book flights to St. Louis if you plan to visit one of these locationsWhy use momondo?
Why should I use momondo to find a flight deal from Islip to St. Louis?
momondo compares prices from hundreds of airlines and agents so you can find and book the best deal on flights from Islip to St. Louis. Millions of users trust and use momondo every year so you are in good hands.
Can I find flights from Islip to St. Louis with flexible booking policies on momondo?
Yes. momondo allows you to filter the results for Islip to St. Louis flights to just show those with flexible booking policies.
How can momondo help me find flights from Islip to St. Louis?
momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from Islip to St. Louis.
I’m not ready to book a flight from Islip to St. Louis right now. Can momondo alert me if prices change?
Price alerts on flights to St. Louis from Islip are quick and easy to set up on momondo. Simply perform a search and select the price alert feature. It is as simple as that.