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Cheap Flights from Islip to St. Louis

Explore the cheapest flights from Islip to St. Louis in the next three months. Based on Trip.com's data from the latest 7 days, one-way fares start at MYR 318, and round-trip tickets start at MYR 591.

      • ISP 20:29
        27h 4m
        1 stop
        STL 22:33
        Islip - St. Louis | Fri, Dec 12 | Frontier Airlines
        STL 15:30
        27h 4m
        1 stop
        ISP 19:34
        St. Louis - Islip | Mon, Dec 15 | Frontier Airlines
        MYR 591 MYR 4,298
        86% OFF
        86% OFF
        MYR 4,298 MYR 591
      • ISP 13:27
        10h 6m
        1 stop
        STL 22:33
        Islip - St. Louis | Fri, Dec 19 | Frontier Airlines
        STL 10:40
        8h
        1 stop
        ISP 19:40
        St. Louis - Islip | Mon, Dec 22 | Frontier Airlines
        MYR 1,195 MYR 4,298
        72% OFF
        72% OFF
        MYR 4,298 MYR 1,195
      • ISP 20:29
        27h 4m
        1 stop
        STL 22:33
        Islip - St. Louis | Tue, Dec 16 | Frontier Airlines
        STL 16:27
        26h 13m
        1 stop
        ISP 19:40
        St. Louis - Islip | Sat, Dec 20 | Frontier Airlines
        MYR 1,259 MYR 4,298
        71% OFF
        71% OFF
        MYR 4,298 MYR 1,259
      • ISP 10:45
        12h 48m
        1 stop
        STL 22:33
        Islip - St. Louis | Tue, Dec 16 | Jetblue Airways
        STL 16:27
        16h 34m
        1 stop
        ISP 10:01
        St. Louis - Islip | Sat, Dec 20 | Frontier Airlines
        MYR 1,611
        63% OFF
        MYR 4,298 MYR 1,611
      • ISP 12:20
        11h 13m
        1 stop
        STL 22:33
        Islip - St. Louis | Tue, Dec 23 | Frontier Airlines
        STL 16:27
        19h 42m
        1 stop
        ISP 13:09
        St. Louis - Islip | Sat, Dec 27 | Frontier Airlines
        MYR 2,721
        37% OFF
        MYR 4,298 MYR 2,721
      • ISP 10:46
        12h 47m
        1 stop
        STL 22:33
        Islip - St. Louis | Tue, Dec 23 | Jetblue Airways
        STL 16:27
        16h 34m
        1 stop
        ISP 10:01
        St. Louis - Islip | Sat, Dec 27 | Frontier Airlines
        MYR 3,868
        10% OFF
        MYR 4,298 MYR 3,868
      • ISP 13:00
        17h 25m
        1 stop
        STL Invalid Date
        Islip - St. Louis | Sat, Dec 13 | Normal Airline
        STL 15:00
        6h
        Direct
        ISP 16:00
        St. Louis - Islip | Mon, Dec 15 | Normal Airline
        Find More Flights
        Find More Flights
      • ISP 15:34
        7h 59m
        1 stop
        STL 22:33
        Islip - St. Louis | Fri, Jan 9 | Frontier Airlines
        MYR 318 MYR 1,359
        77% OFF
        77% OFF
        MYR 1,359 MYR 318
      • ISP 20:54
        27h 39m
        1 stop
        STL 23:33
        Islip - St. Louis | Mon, Jan 19 | Frontier Airlines
        MYR 361 MYR 1,359
        73% OFF
        73% OFF
        MYR 1,359 MYR 361
      • ISP 20:29
        27h 4m
        1 stop
        STL 22:33
        Islip - St. Louis | Tue, Dec 16 | Frontier Airlines
        MYR 407 MYR 1,359
        70% OFF
        70% OFF
        MYR 1,359 MYR 407
      • ISP 10:00
        14h 33m
        1 stop
        STL 23:33
        Islip - St. Louis | Tue, Jan 27 | Jetblue Airways
        MYR 507
        63% OFF
        MYR 1,359 MYR 507
      • ISP 10:00
        13h 33m
        1 stop
        STL 22:33
        Islip - St. Louis | Mon, Jan 12 | Jetblue Airways
        MYR 551
        59% OFF
        MYR 1,359 MYR 551
      • ISP 16:40
        19h 16m
        1 stop
        STL 10:56
        Islip - St. Louis | Mon, Dec 22 | Frontier Airlines
        MYR 634
        53% OFF
        MYR 1,359 MYR 634
      • ISP 21:09
        12h 36m
        1 stop
        STL 08:45
        Islip - St. Louis | Sat, Dec 13 | Frontier Airlines
        MYR 716
        47% OFF
        MYR 1,359 MYR 716
      • ISP 10:45
        12h 48m
        1 stop
        STL 22:33
        Islip - St. Louis | Tue, Dec 16 | Jetblue Airways
        MYR 734
        46% OFF
        MYR 1,359 MYR 734
      • ISP 14:04
        20h 41m
        1 stop
        STL 09:45
        Islip - St. Louis | Sun, Dec 21 | Frontier Airlines
        MYR 790
        42% OFF
        MYR 1,359 MYR 790
      • ISP 10:45
        23h
        1 stop
        STL 08:45
        Islip - St. Louis | Sat, Dec 13 | Jetblue Airways
        MYR 1,223
        10% OFF
        MYR 1,359 MYR 1,223
      • ISP 13:00
        17h 25m
        1 stop
        STL Invalid Date
        Islip - St. Louis | Sat, Dec 13 | Normal Airline
        Find More Flights
        Find More Flights

Crossed out prices are calculated based on the average price of the corresponding route on Trip.com.

Flying from Islip to St. Louis

The distance between Islip and St. Louis is approximately 1,478.87km. Based on Trip.com's data, travel demand peaks in September. The off-season for travel is October.

Cheapest one-way flight priceMYR 318
Cheapest return ticket priceMYR 591
Off-season for travelOctober
Peak season for travelSeptember
Flight distance1,478.87km

Cheapest time to fly from Islip to St. Louis

The cheapest time for Islip to St. Louis flights: Jan 4 to Jan 11 — one way flight prices from MYR 318.

Cheapest flights
From price
Search
  • 714
  • 1421
  • 2128

  • Jan

    284
  • 411
  • 1118
  • 1825

  • Feb

    251
  • 18
  • 815
  • 1522

  • Mar

    221
Displayed prices are calculated based on the lowest average weekly prices of the corresponding route on Trip.com.

Frequently Asked Questions

  • Which airlines offer the cheapest flights from Islip (ISP) to St. Louis (STL)?

    Based on Trip.com data, Frontier Airlines offers one-way fares as low as MYR 318 on Cheapest nonstop routes (e.g. ISP to STL on Fri, Jan 9), while Frontier Airlines offers Cheapest nonstop round-trips from MYR 591 departing on Fri, Dec 12 and returning on Mon, Dec 15.
  • By analyzing data from all airlines on the Trip.com flight calendar, it looks like the best time to book a flight from Islip to St. Louis is around 40 days (6 weeks) in advance, and the best time to fly is usually on Tuesday, Wednesday, and Saturday. Tuesday typically offers the cheapest flights for departure, while Saturday offers the best return deals.
  • To find best deals on flights from Islip to St. Louis, you can use various tools on Trip.com:
    · Be flexible with your travel dates to get the cheapest flight deal. Now the cheapest flight deal is on Fri, Jan 9, with one-way flights priced at just MYR 318.
    · Compare airlines strategically. Budget carriers often provide the lowest base fares, while we found the most affordable airline currently operating on this route is Frontier Airlines.
    · Set up price alerts to easily monitor ticket prices without having to check every day.
    · Check Trip.com flight deals and promo codes frequently.
    · Avoid peak season unless you book very early. It seems the peak season for St. Louis travel is around September.
    · Get exclusive promo codes for Trip.com app users.
  • The cheapest months to fly from Islip to St. Louis is October, when demand for travel is lower.
  • After crunching the numbers on our December flight calendar, it's currently cheapest to fly from Islip to St. Louis on December 12, 2025 with Frontier Airlines, with prices starting at MYR 590.
  • The time difference between St. Louis and Islip is 1h.
  • Tickets can only be changed or cancelled if permitted by airline policy. To submit a change or cancellation request, go to the flight bookings page, select the option to change or cancel your booking, choose the relevant passengers and segment, and submit a request. Please note that additional charges may apply according to the airline ticket policy. However, if the flight has been rescheduled and you would like to change or cancel your ticket, you can submit an involuntary cancellation request. For more details about change and cancellation policies, please check the customer support pages.

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