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Cheap flights from Islip, New York to St. Louis from $105

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from Islip, New York to St. Louis departing on 9/3. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Find the cheapest flights from Islip, New York to St. Louis

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
10:57 am - 4:11 pmISP  Islip Long Island-STL Lambert-St Louis
6h 14m1 stop Orlando
Frontier Logo
6:39 pm - 4:58 pmSTL  Lambert-St Louis-ISP Islip Long Island
21h 19m1 stop Orlando
$225Frontier
Thu, Sep 3 - Thu, Sep 10
Frontier Logo
5:43 pm - 4:34 pmISP  Islip Long Island-STL Lambert-St Louis
23h 51m1 stop Orlando
Frontier Logo
6:39 pm - 4:58 pmSTL  Lambert-St Louis-ISP Islip Long Island
21h 19m1 stop Orlando
$227Frontier
Thu, Sep 24 - Thu, Oct 1
Frontier Logo
7:09 pm - 5:22 pmISP  Islip Long Island-STL Lambert-St Louis
23h 13m2 stops Orlando Atlanta Hartsfield-Jackson
Frontier Logo
6:39 pm - 4:58 pmSTL  Lambert-St Louis-ISP Islip Long Island
21h 19m1 stop Orlando
$268Frontier
Thu, Sep 3 - Thu, Sep 10
Southwest Logo
6:10 am - 11:35 amISP  Islip Long Island-STL Lambert-St Louis
6h 25m1 stop Baltimore/Washington
Southwest Logo
6:45 am - 2:30 pmSTL  Lambert-St Louis-ISP Islip Long Island
6h 45m1 stop Baltimore/Washington
$309Southwest
Thu, Sep 24 - Sat, Sep 26
Southwest Logo
3:20 pm - 9:10 pmISP  Islip Long Island-STL Lambert-St Louis
6h 50m1 stop Baltimore/Washington
Southwest Logo
1:40 pm - 9:10 pmSTL  Lambert-St Louis-ISP Islip Long Island
6h 30m1 stop Baltimore/Washington
$309Southwest
Tue, Sep 1 - Tue, Sep 8
Southwest Logo
6:45 am - 2:55 pmISP  Islip Long Island-STL Lambert-St Louis
9h 10m1 stop Orlando
Southwest Logo
12:55 pm - 9:35 pmSTL  Lambert-St Louis-ISP Islip Long Island
7h 40m1 stop Orlando
$309Southwest
Thu, Sep 3 - Thu, Sep 10
Southwest Logo
6:10 am - 11:35 amISP  Islip Long Island-STL Lambert-St Louis
6h 25m1 stop Baltimore/Washington
Southwest Logo
11:40 am - 9:35 pmSTL  Lambert-St Louis-ISP Islip Long Island
8h 55m2 stops Baltimore/Washington Orlando
$314Southwest
Thu, Sep 3 - Thu, Sep 10
Southwest Logo
1:15 pm - 10:30 pmISP  Islip Long Island-STL Lambert-St Louis
10h 15m2 stops Palm Beach Intl Orlando
Southwest Logo
5:40 pm - 11:35 pmSTL  Lambert-St Louis-ISP Islip Long Island
4h 55m1 stop Baltimore/Washington
$314Southwest
Thu, Sep 24 - Thu, Oct 1
Southwest Logo
6:10 am - 11:35 amISP  Islip Long Island-STL Lambert-St Louis
6h 25m1 stop Baltimore/Washington
Southwest Logo
5:45 am - 2:30 pmSTL  Lambert-St Louis-ISP Islip Long Island
7h 45m2 stops Chicago Midway Baltimore/Washington
$314Southwest
Thu, Sep 24 - Sat, Sep 26
Southwest Logo
6:05 am - 11:20 amISP  Islip Long Island-STL Lambert-St Louis
6h 15m2 stops Baltimore/Washington Chicago Midway
Southwest Logo
1:40 pm - 9:10 pmSTL  Lambert-St Louis-ISP Islip Long Island
6h 30m1 stop Baltimore/Washington
$314Southwest
Tue, Sep 1 - Tue, Sep 8

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Frontier flights from Islip, New York to St. Louis

Our best Frontier deals on Islip, New York to St. Louis flight tickets
Frontier
Sep 3
ISP10:57 amIslip Long Island
6h 14m
1 stop
STL4:11 pmLambert-St Louis
Sep 10
STL6:39 pmLambert-St Louis
21h 19m
1 stop
ISP4:58 pmIslip Long Island
$225
Frontier
Sep 24
ISP5:43 pmIslip Long Island
23h 51m
1 stop
STL4:34 pmLambert-St Louis
Oct 1
STL6:39 pmLambert-St Louis
21h 19m
1 stop
ISP4:58 pmIslip Long Island
$227
Frontier
Sep 3
ISP7:09 pmIslip Long Island
23h 13m
2 stops
STL5:22 pmLambert-St Louis
Sep 10
STL6:39 pmLambert-St Louis
21h 19m
1 stop
ISP4:58 pmIslip Long Island
$268

Southwest flights from Islip, New York to St. Louis

Our best Southwest deals on Islip, New York to St. Louis flight tickets
Southwest
Sep 1
ISP3:20 pmIslip Long Island
6h 50m
1 stop
STL9:10 pmLambert-St Louis
Sep 8
STL1:40 pmLambert-St Louis
6h 30m
1 stop
ISP9:10 pmIslip Long Island
$309
Southwest
Sep 3
ISP6:10 amIslip Long Island
6h 25m
1 stop
STL11:35 amLambert-St Louis
Sep 10
STL11:40 amLambert-St Louis
8h 55m
2 stops
ISP9:35 pmIslip Long Island
$314
Southwest
Sep 3
ISP1:15 pmIslip Long Island
10h 15m
2 stops
STL10:30 pmLambert-St Louis
Sep 10
STL11:40 amLambert-St Louis
8h 55m
2 stops
ISP9:35 pmIslip Long Island
$319

momondo Fare Finder

 
Customize your flight search to find flights from Islip, New York to St. Louis that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, momondo users made 832,500 searches. Data last updated August 5, 2026.
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

Price

Cheapest round-trip

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Thu 9/3

10:57 am-4:11 pm

1 stop6h 14m

Lambert-St Louis

Thu 9/10

6:39 pm-4:58 pm

1 stop21h 19m

$225

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Thu 9/24

5:43 pm-4:34 pm

1 stop23h 51m

Lambert-St Louis

Thu 10/1

6:39 pm-4:58 pm

1 stop21h 19m

$227

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Thu 9/3

7:09 pm-5:22 pm

2 stops23h 13m

Lambert-St Louis

Thu 9/10

6:39 pm-4:58 pm

1 stop21h 19m

$268

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Thu 9/24

6:10 am-11:35 am

1 stop6h 25m

Lambert-St Louis

Sat 9/26

6:45 am-2:30 pm

1 stop6h 45m

$309

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Tue 9/1

3:20 pm-9:10 pm

1 stop6h 50m

Lambert-St Louis

Tue 9/8

1:40 pm-9:10 pm

1 stop6h 30m

$309

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Thu 9/3

6:45 am-2:55 pm

1 stop9h 10m

Lambert-St Louis

Thu 9/10

12:55 pm-9:35 pm

1 stop7h 40m

$309

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Thu 9/3

6:10 am-11:35 am

1 stop6h 25m

Lambert-St Louis

Thu 9/10

11:40 am-9:35 pm

2 stops8h 55m

$314

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Thu 9/24

1:15 pm-10:30 pm

2 stops10h 15m

Lambert-St Louis

Thu 10/1

5:40 pm-11:35 pm

1 stop4h 55m

$314

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Thu 9/24

6:10 am-11:35 am

1 stop6h 25m

Lambert-St Louis

Sat 9/26

5:45 am-2:30 pm

2 stops7h 45m

$314
Quickest round-trip

IslipSt. Louis

ISP Islip Long Island - STL Lambert-St Louis

ISPSTL

Islip Long Island

Tue 9/1

6:05 am-11:20 am

2 stops6h 15m

Lambert-St Louis

Tue 9/8

1:40 pm-9:10 pm

1 stop6h 30m

$314

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 19 resultsSorted by cheapest first
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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 $378. 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 Sunday because tickets tend to average around $488. 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 $382 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 $430 per ticket.

When to book flights from Islip, New York to St. Louis

Are you open to changing your travel dates? Check out the ideal times to fly from Islip, New York to St. Louis according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

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

Fastest flight time

6h 50m

Direct flights

None
The fastest flight from Islip, New York to St. Louis takes 6h 50m
There are no direct flights from Islip, New York to St. Louis. There are no popular flight routes from Islip, New York to St. Louis.
Search flight deals

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 50m.

  • 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?

  • 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?

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
SouthwestPriceFrom $246Free CancellationRating
8.0
4,220 reviews
Search Southwest flights

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
St. Charles
Chesterfield
Fairview Heights
Hermann
St. Peters
Maryland Heights
Florissant
Collinsville
Alton
O'Fallon
Clayton
Farmington
Fenton
Wentzville
Festus
Eureka
Edwardsville
Litchfield
Grafton
Shrewsbury

Why 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.

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