$80+ Cheap flights from St. Louis (STL) to Key Largo, FL
This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 4/25. Fares are subject to change and may not be available on all flights or dates of travel.
STL — MIA
Apr 26 — May 31
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 August, booked 33 days in advance, depart on a Sunday or Monday 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 March 27, 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 March 27, 2026.
This American Airlines deal was found by Cheapflights users on 3/25. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 5/135:24 am
STL
- MIA
Nonstop2h 51m
American Airlines
Wed 5/208:15 am
MIA
- STL
Nonstop3h 01m
American Airlines
Deal found 3/25![American Airlines logo]()
$275
This Frontier deal was found by Cheapflights users on 3/25. 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.
Sun 4/1211:33 am
STL
- MIA
1 stop5h 44m
Frontier
Fri 4/177:00 am
MIA
- STL
1 stop13h 21m
Frontier
Deal found 3/25![Frontier logo]()
$276
This CheapOair deal was found by Cheapflights users on 3/27. 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.
Thu 5/1412:16 pm
STL
- MIA
1 stop17h 44m
Frontier
Fri 5/226:00 am
MIA
- STL
1 stop14h 23m
Frontier
Deal found 3/27![Frontier logo]()
$277
This Kiwi.com deal was found by Cheapflights users on 3/24. 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 5/38:06 pm
STL
- MIA
2 stops13h 06m
Multiple Airlines
Mon 5/116:11 pm
MIA
- STL
1 stop24h 22m
Multiple Airlines
Deal found 3/24![Multiple Airlines logo]()
$278
This Kiwi.com deal was found by Cheapflights users on 3/22. 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.
Tue 5/126:33 pm
STL
- MIA
1 stop20h 54m
Multiple Airlines
Sat 5/168:00 am
MIA
- STL
2 stops12h 23m
Multiple Airlines
Deal found 3/22![Multiple Airlines logo]()
$279
This Priceline deal was found by Cheapflights users on 3/22. 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.
Thu 4/26:29 pm
STL
- MIA
1 stop5h 20m
Frontier
Tue 4/75:05 am
MIA
- STL
1 stop6h 25m
Frontier
Deal found 3/22![Frontier logo]()
$280
This CheapOair deal was found by Cheapflights users on 3/24. 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 3/258:12 pm
STL
- MIA
1 stop8h 26m
Frontier
Fri 3/275:50 am
MIA
- STL
1 stop28h 59m
Frontier
Deal found 3/24![Frontier logo]()
$281
This Kiwi.com deal was found by Cheapflights users on 3/22. 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 4/158:23 pm
STL
- MIA
1 stop11h 32m
Multiple Airlines
Thu 4/235:05 am
MIA
- STL
1 stop6h 25m
Multiple Airlines
Deal found 3/22![Multiple Airlines logo]()
$282
This Kiwi.com deal was found by Cheapflights users on 3/25. 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.
Thu 5/216:33 pm
STL
- MIA
1 stop27h 56m
Multiple Airlines
Thu 5/281:10 pm
MIA
- STL
1 stop5h 23m
Multiple Airlines
Deal found 3/25![Multiple Airlines logo]()
$283
This Kiwi.com deal was found by Cheapflights users on 3/22. 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 4/244:59 pm
STL
- MIA
2 stops18h 57m
Multiple Airlines
Sun 4/2612:53 pm
MIA
- STL
1 stop18h 57m
Multiple Airlines
Deal found 3/22![Multiple Airlines logo]()
$284
This Southwest deal was found by Cheapflights users on 3/25. 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.
Wed 4/151:10 pm
STL
- MIA
Nonstop2h 40m
Southwest
Tue 4/217:00 am
MIA
- STL
1 stop4h 50m
Southwest
Deal found 3/25![Southwest logo]()
$285
This Southwest deal was found by Cheapflights users on 3/23. 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 4/282:30 pm
STL
- MIA
1 stop5h 10m
Southwest
Wed 4/293:00 pm
MIA
- STL
Nonstop2h 55m
Southwest
Deal found 3/23![Southwest logo]()
$286
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 March 27, 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 March 27, 2026.
This Southwest deal was found by Cheapflights users on 3/26. 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 4/252:25 pm
STL
- MIA
1 stop4h 55m
Southwest
Tue 4/283:00 pm
MIA
- STL
Nonstop2h 55m
Southwest
Deal found 3/26![Southwest logo]()
$316
This United Airlines deal was found by Cheapflights users on 3/25. 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.
Tue 5/57:45 am
STL
- MIA
2 stops12h 26m
United Airlines
Wed 5/610:16 am
MIA
- STL
2 stops11h 57m
United Airlines
Deal found 3/25![United Airlines logo]()
$395
This Delta deal was found by Cheapflights users on 3/22. 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.
Wed 5/61:03 pm
STL
- MIA
1 stop4h 32m
Delta
Mon 5/117:39 pm
MIA
- STL
1 stop5h 20m
Delta
Deal found 3/22![Delta logo]()
$405
This Southwest deal was found by Cheapflights users on 3/25. 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 4/281:10 pm
STL
- MIA
Nonstop2h 40m
Southwest
Thu 4/306:20 am
MIA
- STL
2 stops7h 30m
Southwest
Deal found 3/25![Southwest logo]()
$321
This Southwest deal was found by Cheapflights users on 3/26. 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 4/2111:35 am
STL
- MIA
2 stops9h 20m
Southwest
Sat 4/256:35 am
MIA
- STL
2 stops8h 00m
Southwest
Deal found 3/26![Southwest logo]()
$336
This Delta deal was found by Cheapflights users on 3/25. 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 4/146:00 am
STL
- MIA
1 stop7h 12m
Delta
Sun 4/196:00 am
MIA
- STL
1 stop5h 34m
Delta
Deal found 3/25![Delta logo]()
$458
This United Airlines deal was found by Cheapflights users on 3/23. 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.
Thu 4/166:00 am
STL
- MIA
1 stop8h 47m
United Airlines
Wed 4/229:15 am
MIA
- STL
2 stops13h 37m
United Airlines
Deal found 3/23![United Airlines logo]()
$490
This Southwest deal was found by Cheapflights users on 3/22. 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 7/2012:45 pm
STL
- MIA
Nonstop2h 40m
Southwest
Fri 7/245:40 am
MIA
- STL
Nonstop2h 50m
Southwest
Deal found 3/22![Southwest logo]()
$439
This Southwest deal was found by Cheapflights users on 3/24. 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 4/172:15 pm
STL
- MIA
2 stops6h 45m
Southwest
Sat 4/186:15 am
MIA
- STL
2 stops8h 45m
Southwest
Deal found 3/24![Southwest logo]()
$453
This Southwest deal was found by Cheapflights users on 3/23. 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.
Sun 8/28:05 am
STL
- MIA
1 stop5h 25m
Southwest
Fri 8/712:05 pm
MIA
- STL
2 stops8h 50m
Southwest
Deal found 3/23![Southwest logo]()
$464
This Southwest deal was found by Cheapflights users on 3/23. 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 4/231:45 pm
STL
- MIA
2 stops6h 40m
Southwest
Sun 4/266:10 am
MIA
- STL
2 stops9h 25m
Southwest
Deal found 3/23![Southwest logo]()
$469
This Southwest deal was found by Cheapflights users on 3/25. 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.
Wed 7/295:50 am
STL
- MIA
2 stops9h 00m
Southwest
Sun 8/25:00 am
MIA
- STL
2 stops8h 45m
Southwest
Deal found 3/25![Southwest logo]()
$500
Last-minute flights from St. Louis to Key LargoDiscover last-minute flight deals from St. Louis to Key Largo. Data last updated March 27, 2026 and is based on user searches.
Discover last-minute flight deals from St. Louis to Key Largo. Data last updated March 27, 2026 and is based on user searches.
This Kiwi.com deal was found by Cheapflights users on 3/26. 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 4/14:54 pm
STL
- MIA
2 stops14h 06m
Frontier
Mon 4/67:12 pm
MIA
- STL
1 stop16h 18m
Frontier
Deal found 3/26![Frontier logo]()
$403
This Kiwi.com deal was found by Cheapflights users on 3/27. 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 4/14:54 pm
STL
- MIA
2 stops14h 06m
Multiple Airlines
Wed 4/83:12 pm
MIA
- STL
1 stop27h 22m
Multiple Airlines
Deal found 3/27![Multiple Airlines logo]()
$404
This Priceline deal was found by Cheapflights users on 3/24. 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.
Thu 4/26:29 pm
STL
- MIA
1 stop5h 20m
Frontier
Sun 4/55:05 am
MIA
- STL
1 stop6h 25m
Frontier
Deal found 3/24![Frontier logo]()
$305
This Kiwi.com deal was found by Cheapflights users on 3/26. 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.
Thu 4/210:12 pm
STL
- MIA
2 stops43h 05m
Frontier
Thu 4/99:10 am
MIA
- STL
1 stop9h 24m
Frontier
Deal found 3/26![Frontier logo]()
$310
This Frontier deal was found by Cheapflights users on 3/27. 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.
Fri 4/38:16 pm
STL
- MIA
1 stop8h 33m
Frontier
Tue 4/75:05 am
MIA
- STL
1 stop6h 25m
Frontier
Deal found 3/27![Frontier logo]()
$301
This Kiwi.com deal was found by Cheapflights users on 3/23. 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 4/38:16 pm
STL
- MIA
2 stops21h 01m
Frontier
Mon 4/69:05 am
MIA
- STL
1 stop26h 25m
Frontier
Deal found 3/23![Frontier logo]()
$388
This Kiwi.com deal was found by Cheapflights users on 3/24. 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 4/510:12 pm
STL
- MIA
2 stops35h 10m
Frontier
Sun 4/125:05 am
MIA
- STL
1 stop6h 33m
Frontier
Deal found 3/24![Frontier logo]()
$416
This Kiwi.com deal was found by Cheapflights users on 3/23. 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 4/68:41 am
STL
- MIA
2 stops15h 08m
Frontier
Thu 4/95:05 am
MIA
- STL
1 stop13h 29m
Frontier
Deal found 3/23![Frontier logo]()
$319
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 March 27, 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 March 27, 2026.
This Frontier deal was found by Cheapflights users on 3/26. 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.
Sat 4/258:17 pm
STL
- MIA
1 stop7h 48m
Frontier
Deal found 3/26![Frontier logo]()
$80
This Kiwi.com deal was found by Cheapflights users on 3/25. 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 4/228:23 pm
STL
- MIA
1 stop25h 08m
Multiple Airlines
Deal found 3/25![Multiple Airlines logo]()
$83
This Frontier deal was found by Cheapflights users on 3/24. 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.
Fri 4/178:39 am
STL
- MIA
1 stop11h 11m
Frontier
Deal found 3/24![Frontier logo]()
$86
This Kiwi.com deal was found by Cheapflights users on 3/27. 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.
Tue 5/126:33 pm
STL
- MIA
1 stop20h 54m
Frontier
Deal found 3/27![Frontier logo]()
$94
This Kiwi.com deal was found by Cheapflights users on 3/27. 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 4/298:23 pm
STL
- MIA
1 stop11h 32m
Multiple Airlines
Deal found 3/27![Multiple Airlines logo]()
$95
This Kiwi.com deal was found by Cheapflights users on 3/27. 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.
Thu 5/76:55 pm
STL
- MIA
1 stop20h 32m
Frontier
Deal found 3/27![Frontier logo]()
$96
This Super.com deal was found by Cheapflights users on 3/24. 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 Super.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 4/108:16 pm
STL
- MIA
1 stop8h 33m
Frontier
Deal found 3/24![Frontier logo]()
$99
This Frontier deal was found by Cheapflights users on 3/27. 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 4/138:19 pm
STL
- MIA
1 stop8h 30m
Frontier
Deal found 3/27![Frontier logo]()
$100
This Frontier deal was found by Cheapflights users on 3/25. 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.
Wed 5/206:51 pm
STL
- MIA
1 stop11h 09m
Frontier
Deal found 3/25![Frontier logo]()
$101
This Kiwi.com deal was found by Cheapflights users on 3/27. 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.
Tue 5/266:33 pm
STL
- MIA
1 stop27h 14m
Frontier
Deal found 3/27![Frontier logo]()
$104
This Kiwi.com deal was found by Cheapflights users on 3/26. 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.
Thu 5/286:33 pm
STL
- MIA
1 stop27h 14m
Frontier
Deal found 3/26![Frontier logo]()
$106
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 March 27, 2026.
Most accurate provider | FlightHub 3 stars |
|---|---|
Most trusted provider | FlightHub 3 stars |
Round-trip from | $275 (American Airlines) |
One-way from | $80 (Frontier) |
Popular in | March |
Cheapest in | September |
Average price | $460 |
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 2,558,603 searches. Data last updated March 27, 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 - MIA
STLMIA
Lambert-St Louis
Sat 4/25
2:25 pm-8:20 pm
1 stop4h 55m
Miami
Tue 4/28
3:00 pm-4:55 pm
Nonstop2h 55m
$316
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Tue 4/28
1:10 pm-4:50 pm
Nonstop2h 40m
Miami
Thu 4/30
6:20 am-12:50 pm
2 stops7h 30m
$321
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Tue 4/21
11:35 am-9:55 pm
2 stops9h 20m
Miami
Sat 4/25
6:35 am-1:35 pm
2 stops8h 00m
$336
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Tue 5/5
7:45 am-9:11 pm
2 stops12h 26m
Miami
Wed 5/6
10:16 am-9:13 pm
2 stops11h 57m
$395
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Wed 5/6
1:03 pm-6:35 pm
1 stop4h 32m
Miami
Mon 5/11
7:39 pm-11:59 pm
1 stop5h 20m
$405
Quickest round-trip
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Mon 7/20
12:45 pm-4:25 pm
Nonstop2h 40m
Miami
Fri 7/24
5:40 am-7:30 am
Nonstop2h 50m
$439
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Fri 4/17
2:15 pm-10:00 pm
2 stops6h 45m
Miami
Sat 4/18
6:15 am-2:00 pm
2 stops8h 45m
$453
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Tue 4/14
6:00 am-2:12 pm
1 stop7h 12m
Miami
Sun 4/19
6:00 am-10:34 am
1 stop5h 34m
$458
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Sun 8/2
8:05 am-2:30 pm
1 stop5h 25m
Miami
Fri 8/7
12:05 pm-7:55 pm
2 stops8h 50m
$464
St. LouisMiami
STL - MIA
STLMIA
Lambert-St Louis
Thu 4/23
1:45 pm-9:25 pm
2 stops6h 40m
Miami
Sun 4/26
6:10 am-2:35 pm
2 stops9h 25m
$469
Showing 1-10 of 23 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
How far ahead should I book a flight from St. Louis to Key Largo?
Use this chart to determine the optimal time to book a round-trip flight from St. Louis to Key Largo. Price data was last updated on March 13, 2026.
To ensure you get the cheapest price possible for a flight from St. Louis to Key Largo, you should look to book at least 33 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.
What is the cheapest month to book a flight from St. Louis to Key Largo?
Currently, April is the cheapest month in which you can book a flight from St. Louis to Key Largo (average of $68). Flying from St. Louis to Key Largo in February is currently the most expensive (average of $222). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.
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 March 27, 2026.
It’s optimal to fly from St. Louis to Key Largo in the evening. By choosing this option you can save up to 16% on the cost of your flight, compared to a flight in the morning.
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 March 23, 2026.
Travelers seeking maximum savings on their St. Louis to Key Largo flight should consider departing on Thursday mornings when fares are most often at their lowest. Thursday at noon flights should be avoided if possible as fares are typically the most expensive at this time.
Weekly flight availability from St. Louis to Key Largo
Explore weekly flight availability from St. Louis to Key Largo. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated March 27, 2026.
The most flights from STL to KE9 are scheduled on a Wednesday (7 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (2 on average).
How much does it cost to fly round-trip from St. Louis to Key Largo?
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 March 27, 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.
Boarding
8.1
Crew
8.6
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Boarding
8.1
Crew
8.6
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Boarding
8.1
Crew
8.6
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Boarding
8.1
Crew
8.6
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Boarding
8.1
Crew
8.6
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Boarding
8.1
Crew
8.6
Comfort
8.0
Food
7.0
Overall
8.0
Entertainment
7.5
Reviews
1 / 20
2.0
MediocreDominic,Mar 2026
MCO - SMF
Related info for your journey
Find useful and relevant information for your journey from St. Louis to Key Largo. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.
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Alternative routes for St. Louis to Key Largo
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Complete your trip
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St. Louis and Key Largo flights
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Other flights from St. Louis
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St. Louis to Key Largo flights
Consider these flights traveling from St. Louis to Key Largo.
Top 7 airlines flying from St. Louis to Key Largo
Discover the top 7 airlines that operate flights from St. Louis to Key Largo. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated March 27, 2026.
| Airline | Cheapest | Average | Flexibility | On-time |
|---|---|---|---|---|
| Cheapest$74 | Average$158 | FlexibilityNo cancel fee | On-time65% | |
| Cheapest$124 | Average$376 | FlexibilityNo cancel fee | On-timeN/A | |
| Cheapest$127 | Average$218 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$150 | Average$460 | FlexibilityNo cancel fee | On-time69% | |
| Cheapest$186 | Average$405 | FlexibilityNo cancel fee | On-time71% | |
| Cheapest$220 | Average$408 | FlexibilityNo cancel fee | On-time62% | |
| Cheapest$235 | Average$449 | FlexibilityNo cancel fee | On-time63% |