$54+ Cheap flights from St. Louis (STL) to Key Largo, FL
This is the cheapest round-trip flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 10/7. Fares are subject to change and may not be available on all flights or dates of travel.
STL — MIA
Oct 10 — Oct 171
Round-trip
1 adult, Economy
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Find cheap flights from St. Louis to Key Largo with Cheapflights
1. Tell us where you want to go
Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”2. Select your favorite providers
We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.3. Compare prices and book
Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.Cheapflights Tip: The best prices from Lambert-St Louis to Key Largo are usually found in September or October, booked 84 days in advance, depart on a Monday or Saturday and return on a Thursday
Cheap flight deals from St. Louis to Key Largo
Cheapest
Best
Last-minute
One-way
Cheapest flights from St. Louis to Key LargoExplore the most affordable flight options available from St. Louis to Key Largo. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 10, 2026.
Explore the most affordable flight options available from St. Louis to Key Largo. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 10, 2026.
This Kiwi.com deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/252:29 pm -
1 stop19h 01m
Thu 10/19:30 pm -
1 stop16h 40m
Deal found 9/5![Frontier logo]()
$269
This Kiwi.com deal was found by Cheapflights users on 9/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/255:19 pm -
2 stops26h 19m
Fri 10/25:32 am -
1 stop8h 38m
Deal found 9/6![Frontier logo]()
$271
This Kiwi.com deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/275:19 pm -
2 stops22h 10m
Thu 10/19:30 pm -
1 stop16h 40m
Deal found 9/5![Frontier logo]()
$272
This Southwest deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/104:55 pm -
Nonstop2h 50m
Mon 10/125:20 am -
1 stop6h 40m
Deal found 9/9![Southwest logo]()
$273
This Kiwi.com deal was found by Cheapflights users on 9/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/275:19 pm -
2 stops22h 10m
Wed 9/305:32 am -
1 stop8h 38m
Deal found 9/8![Frontier logo]()
$274
This Southwest deal was found by Cheapflights users on 9/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/104:55 pm -
Nonstop2h 50m
Tue 10/134:30 pm -
Nonstop2h 50m
Deal found 9/6![Southwest logo]()
$275
This CheapOair deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/162:29 pm -
1 stop5h 09m
Wed 9/235:32 am -
1 stop8h 38m
Deal found 9/5![Frontier logo]()
$276
This Kiwi.com deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/232:29 pm -
1 stop5h 09m
Sun 10/411:30 pm -
2 stops14h 40m
Deal found 9/5![Frontier logo]()
$277
This Frontier deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/72:59 pm -
1 stop8h 53m
Mon 12/146:40 am -
1 stop13h 14m
Deal found 9/5![Frontier logo]()
$278
This Kiwi.com deal was found by Cheapflights users on 9/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/136:44 pm -
1 stop21h 20m
Mon 11/239:19 am -
2 stops15h 40m
Deal found 9/7![Frontier logo]()
$279
This Frontier deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/212:29 pm -
1 stop5h 04m
Fri 9/255:32 am -
1 stop8h 38m
Deal found 9/9![Frontier logo]()
$280
This Southwest deal was found by Cheapflights users on 9/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/210:15 am -
1 stop5h 10m
Sat 11/145:55 am -
Nonstop2h 55m
Deal found 9/7![Southwest logo]()
$281
Best flights from St. Louis to Key LargoDiscover carefully curated flight deals from St. Louis to Key Largo that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 10, 2026.
Discover carefully curated flight deals from St. Louis to Key Largo that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated September 10, 2026.
This Southwest deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/712:40 pm -
1 stop7h 15m
Sat 12/125:55 am -
Nonstop2h 55m
Deal found 9/5![Southwest logo]()
$285
This Delta deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/242:21 pm -
1 stop6h 05m
Tue 12/17:10 am -
1 stop7h 18m
Deal found 9/9![Delta logo]()
$332
This United Airlines deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/27:30 am -
2 stops11h 11m
Tue 11/34:25 pm -
1 stop6h 15m
Deal found 9/9![United Airlines logo]()
$352
This Southwest deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 1/710:20 am -
1 stop4h 35m
Mon 1/119:30 am -
1 stop9h 30m
Deal found 9/9![Southwest logo]()
$288
This Southwest deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/2411:55 am -
2 stops9h 15m
Mon 10/266:40 am -
1 stop6h 35m
Deal found 9/5![Southwest logo]()
$300
This Southwest deal was found by Cheapflights users on 9/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/302:30 pm -
2 stops7h 40m
Sat 10/316:45 am -
2 stops10h 00m
Deal found 9/8![Southwest logo]()
$326
This Southwest deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 11/310:55 am -
2 stops8h 10m
Sun 11/156:50 am -
1 stop6h 30m
Deal found 9/9![Southwest logo]()
$353
This Southwest deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 3/111:30 am -
Nonstop2h 40m
Fri 3/52:40 pm -
1 stop5h 30m
Deal found 9/5![Southwest logo]()
$357
This Southwest deal was found by Cheapflights users on 9/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/232:30 pm -
2 stops7h 40m
Fri 10/306:10 pm -
2 stops6h 30m
Deal found 9/6![Southwest logo]()
$385
This Southwest deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/1010:05 am -
2 stops9h 30m
Tue 10/1312:05 pm -
2 stops7h 55m
Deal found 9/5![Southwest logo]()
$401
Last-minute flights from St. Louis to Key LargoDiscover last-minute flight deals from St. Louis to Key Largo. Data last updated September 10, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Key Largo. Data last updated September 10, 2026 and is based on user searches.
This CheapOair deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/162:29 pm -
1 stop5h 09m
Wed 9/235:32 am -
1 stop8h 38m
Deal found 9/5![Frontier logo]()
$276
This Frontier deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/212:29 pm -
1 stop5h 04m
Fri 9/255:32 am -
1 stop8h 38m
Deal found 9/9![Frontier logo]()
$280
This Kiwi.com deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/232:29 pm -
1 stop5h 09m
Sun 10/411:30 pm -
2 stops14h 40m
Deal found 9/5![Frontier logo]()
$277
This Kiwi.com deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/232:29 pm -
1 stop5h 09m
Sat 10/35:22 am -
2 stops36h 12m
Deal found 9/5![Frontier logo]()
$283
This Kiwi.com deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/252:29 pm -
1 stop19h 01m
Thu 10/19:30 pm -
1 stop16h 40m
Deal found 9/5![Frontier logo]()
$269
This Kiwi.com deal was found by Cheapflights users on 9/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/255:19 pm -
2 stops26h 19m
Fri 10/25:32 am -
1 stop8h 38m
Deal found 9/6![Frontier logo]()
$271
This Kiwi.com deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/275:19 pm -
2 stops22h 10m
Thu 10/19:30 pm -
1 stop16h 40m
Deal found 9/5![Frontier logo]()
$272
This Kiwi.com deal was found by Cheapflights users on 9/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 9/275:19 pm -
2 stops22h 10m
Wed 9/305:32 am -
1 stop8h 38m
Deal found 9/8![Frontier logo]()
$274
This Frontier deal was found by Cheapflights users on 9/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/110:20 am -
1 stop10h 40m
Sat 10/35:55 am -
1 stop14h 22m
Deal found 9/6![Frontier logo]()
$278
This Southwest deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/104:55 pm -
Nonstop2h 50m
Mon 10/125:20 am -
1 stop6h 40m
Deal found 9/9![Southwest logo]()
$273
This Southwest deal was found by Cheapflights users on 9/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/104:55 pm -
Nonstop2h 50m
Tue 10/134:30 pm -
Nonstop2h 50m
Deal found 9/6![Southwest logo]()
$275
This Kiwi.com deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/104:30 pm -
2 stops21h 55m
Tue 10/1310:36 pm -
1 stop20h 04m
Deal found 9/5![Frontier logo]()
$282
One-way flights from St. Louis to Key LargoSearch for one-way flight options from St. Louis to Key Largo. Find affordable one-way fares based on user searches. Data last updated September 10, 2026.
Search for one-way flight options from St. Louis to Key Largo. Find affordable one-way fares based on user searches. Data last updated September 10, 2026.
This Priceline deal was found by Cheapflights users on 9/8. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/72:29 pm -
1 stop5h 09m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/8![Frontier logo]()
$54
This Trip.com deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 9/302:29 pm -
1 stop5h 09m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/9![Frontier logo]()
$55
This Trip.com deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 10/126:35 pm -
1 stop14h 40m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/9![Frontier logo]()
$62
This Kiwi.com deal was found by Cheapflights users on 9/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/96:44 pm -
1 stop25h 47m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/7![Frontier logo]()
$65
This Kiwi.com deal was found by Cheapflights users on 9/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/166:44 pm -
1 stop14h 45m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/7![Frontier logo]()
$66
This Kiwi.com deal was found by Cheapflights users on 9/7. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/236:35 pm -
1 stop14h 40m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/7![Frontier logo]()
$72
This Kiwi.com deal was found by Cheapflights users on 9/9. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/96:35 pm -
1 stop25h 54m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/9![Frontier logo]()
$77
This Kiwi.com deal was found by Cheapflights users on 9/6. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 12/42:59 pm -
1 stop26h 16m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/6![Frontier logo]()
$78
This CheapOair deal was found by Cheapflights users on 9/5. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 11/136:44 pm -
1 stop21h 20m
Wed 12/3112:00 am -
Nonstop0h 00m
Deal found 9/5![Frontier logo]()
$79
Find flight deals from St. Louis to Key Largo
Keep the following information in mind while searching for St. Louis to Key Largo flight deals. Data was last updated September 10, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $269 (Kiwi.com) |
One-way from | $54 (Priceline) |
Popular in | June |
Cheapest in | September |
Average price | $351 |
Cheapflights Fare Finder
Customize your flight search to find flights from St. Louis to Key Largo 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, Cheapflights users made 7,457,451 searches. Data last updated September 10, 2026.
Use the filters below to find and compare flights from St. Louis to Key Largo that are best for you.
Fly from
Fly to
Route
Depart
Return
Cheapest round-trip
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Tue 12/15
11:05 am-7:41 pm
1 stop7h 36m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$124
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Thu 10/29
5:35 pm-12:53 am
1 stop6h 18m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$129
Quickest round-trip
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Wed 10/14
2:38 pm-9:16 pm
1 stop5h 38m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$129
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Mon 12/7
12:40 pm-10:10 pm
2 stops8h 30m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$134
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Sat 12/5
6:25 am-1:40 pm
1 stop6h 15m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$148
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Sat 11/7
5:38 pm-12:53 am
1 stop6h 15m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$148
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Fri 12/11
5:05 am-11:05 pm
2 stops17h 00m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$151
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Tue 11/3
7:00 am-3:04 pm
1 stop7h 04m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$158
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Thu 10/15
5:35 pm-12:53 am
1 stop6h 18m
Miami
Wed 12/31
12:00 am-11:00 pm
Nonstop0h 00m
$158
St. LouisMiami
STL Lambert-St Louis - MIA Miami
STLMIA
Lambert-St Louis
Mon 12/7
12:40 pm-8:55 pm
1 stop7h 15m
Miami
Sat 12/12
5:55 am-7:50 am
Nonstop2h 55m
$285
Showing 1-10 of 19 resultsSorted by cheapest first
Best time to book a flight from St. Louis to Key Largo
Have a flexible travel schedule? Discover the best time to fly to Key Largo from St. Louis with our price prediction graph.
STL-MIA
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.
Cheapflights Insights
Everything you need to know about your flight from St. Louis to Key Largo
STL-KE9
STL-MIA
What is the cheapest time of day to fly from STL to KE9?
Find hourly flight availability from St. Louis to Key Largo. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 10, 2026.
It’s optimal to fly from St. Louis to Key Largo in the evening. By choosing this option you can save up to 18% on the cost of your flight, compared to a flight in the afternoon.
How much does it cost to fly round-trip from St. Louis to Key Largo?
Airfare is below average for this route at the moment.
St. Louis to Key Largo flights typically cost between $277 and $415 in September.The cheapest round-trip price found within the last 5 days was $269 on Frontier (Sep 25-Oct 1).
What is the cheapest day to fly from St. Louis to Key Largo?
Use this chart to determine the cheapest time to fly round-trip from St. Louis to Key Largo. Price data was last updated on September 5, 2026.
Travelers seeking maximum savings on their St. Louis to Key Largo flight should consider departing on Friday at noon when fares are most often at their lowest. Tuesday evenings flights should be avoided if possible as fares are typically the most expensive at this time.
Reviews of airlines servicing Key Largo
Get insights into the airlines that provide service to Key Largo. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to Key Largo. Reviews last updated September 10, 2026.
Peruse reviews from past customers who have flown with Southwest,Delta, andAmerican Airlines from St. Louis to Key Largo to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodScott,Feb 2026
HOU - FLL
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodScott,Feb 2026
HOU - FLL
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodScott,Feb 2026
HOU - FLL
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodScott,Feb 2026
HOU - FLL
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodScott,Feb 2026
HOU - FLL
Crew
8.6
Overall
8.0
Boarding
8.1
Comfort
8.0
Food
7.0
Entertainment
7.5
Reviews
1 / 20
6.0
GoodScott,Feb 2026
HOU - FLL
Related info for your journey
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Top 6 airlines flying from St. Louis to Key Largo
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| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$127 | Average$232 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$150 | Average$456 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$191 | Average$433 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$220 | Average$408 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$228 | Average$446 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$279 | Average$461 | FlexibilityNo cancel fee | On-time63% |