Key Largo

$81+ 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 7/30. Fares are subject to change and may not be available on all flights or dates of travel.
STL — MIA
Jul 31 — Aug 71
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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 Saturday or Sunday and return on a Thursday

Cheap flight deals from St. Louis to Key Largo

Cheapest flights from St. Louis to Key Largo
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 July 1, 2026.

This Kiwi.com deal was found by Cheapflights users on 6/29. 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 7/244:57 pm
STL
-
MIA
1 stop19h 56m
Frontier
Sun 8/28:30 am
MIA
-
STL
1 stop10h 07m
Frontier
Deal found 6/29$275
This Frontier deal was found by Cheapflights users on 6/27. 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 10/1610:35 am
STL
-
MIA
1 stop6h 47m
Frontier
Tue 10/207:20 am
MIA
-
STL
1 stop12h 55m
Frontier
Deal found 6/27$276
This Kiwi.com deal was found by Cheapflights users on 6/28. 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 9/56:45 pm
STL
-
MIA
2 stops17h 47m
Frontier
Sat 9/1210:09 pm
MIA
-
STL
1 stop12h 31m
Frontier
Deal found 6/28$277
This Kiwi.com deal was found by Cheapflights users on 6/28. 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 7/196:34 pm
STL
-
MIA
1 stop18h 19m
Frontier
Sun 7/2610:15 pm
MIA
-
STL
2 stops44h 22m
Frontier
Deal found 6/28$278
This Southwest deal was found by Cheapflights users on 6/28. 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 7/252:10 pm
STL
-
MIA
1 stop7h 35m
Southwest
Mon 7/277:15 am
MIA
-
STL
Nonstop2h 50m
Southwest
Deal found 6/28$279
This CheapOair deal was found by Cheapflights users on 6/28. 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 8/74:57 pm
STL
-
MIA
1 stop5h 09m
Frontier
Sun 8/910:15 pm
MIA
-
STL
1 stop21h 00m
Frontier
Deal found 6/28$280
This American Airlines deal was found by Cheapflights users on 6/25. 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.
Tue 11/245:21 am
STL
-
MIA
Nonstop2h 48m
American Airlines
Tue 12/18:28 pm
MIA
-
STL
Nonstop3h 04m
American Airlines
Deal found 6/25$281
This Kiwi.com deal was found by Cheapflights users on 6/30. 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 7/196:34 pm
STL
-
MIA
1 stop18h 19m
Frontier
Fri 7/245:28 pm
MIA
-
STL
1 stop16h 29m
Frontier
Deal found 6/30$282
This Kiwi.com deal was found by Cheapflights users on 6/30. 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 7/196:34 pm
STL
-
MIA
1 stop18h 19m
Frontier
Mon 8/106:42 pm
MIA
-
STL
1 stop23h 55m
Frontier
Deal found 6/30$283
This Frontier deal was found by Cheapflights users on 6/28. 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 7/174:57 pm
STL
-
MIA
1 stop5h 08m
Frontier
Sat 7/256:50 am
MIA
-
STL
1 stop9h 06m
Frontier
Deal found 6/28$284
This Kiwi.com deal was found by Cheapflights users on 6/28. 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 7/228:08 pm
STL
-
MIA
2 stops16h 45m
Frontier
Fri 7/315:28 pm
MIA
-
STL
1 stop16h 29m
Frontier
Deal found 6/28$285
This Frontier deal was found by Cheapflights users on 6/28. 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 7/228:08 pm
STL
-
MIA
1 stop8h 43m
Frontier
Sun 8/26:00 am
MIA
-
STL
1 stop14h 23m
Frontier
Deal found 6/28$286

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 July 1, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$275
(Kiwi.com)

One-way from

$81
(Trip.com)

Popular in

June

Cheapest in

September

Average price

$430
Provider with most accurate pricing for Lambert-St Louis-Miami flight deals.
Provider most trusted by Cheapflights users for Lambert-St Louis-Miami flights.
From Lambert-St Louis to Key Largo
One-way flight from Lambert-St Louis to Key Largo
Highest demand for flights based on searches. 9% potential increase in price ($42 potential increase over avg. RT price).
Cheapest flight prices on average. 1% potential price decrease ($6 potential savings vs. average RT price).
Average for round-trip flights in July 2026

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 July 1, 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

Price

Cheapest round-trip

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Wed 9/16

6:00 am-1:05 pm

1 stop6h 05m

Miami

Wed 9/23

1:12 pm-8:35 pm

1 stop8h 23m

$289
Quickest round-trip

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Tue 7/21

12:45 pm-4:25 pm

Nonstop2h 40m

Miami

Tue 7/28

7:40 am-9:30 am

Nonstop2h 50m

$297

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Tue 9/1

6:30 am-3:30 pm

2 stops8h 00m

Miami

Tue 9/8

7:10 am-12:10 pm

2 stops6h 00m

$299

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Sat 7/25

10:20 am-10:10 pm

2 stops10h 50m

Miami

Sat 8/1

6:10 am-3:20 pm

2 stops10h 10m

$311

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Mon 7/20

12:45 pm-4:25 pm

Nonstop2h 40m

Miami

Fri 7/24

7:15 am-9:05 am

Nonstop2h 50m

$313

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Sat 9/19

7:50 am-7:15 pm

2 stops10h 25m

Miami

Tue 9/29

9:15 am-5:55 pm

2 stops9h 40m

$333

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Mon 8/17

12:30 pm-4:10 pm

Nonstop2h 40m

Miami

Fri 8/21

4:50 pm-10:25 pm

1 stop6h 35m

$339

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Wed 9/23

10:45 am-8:10 pm

2 stops8h 25m

Miami

Mon 9/28

4:50 pm-10:05 pm

2 stops6h 15m

$344

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Thu 7/23

12:45 pm-4:25 pm

Nonstop2h 40m

Miami

Mon 7/27

7:15 am-9:05 am

Nonstop2h 50m

$359

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

Sat 9/12

5:45 am-4:15 pm

2 stops9h 30m

Miami

Fri 9/18

4:50 pm-10:05 pm

2 stops6h 15m

$359

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/28

Showing 1-10 of 23 resultsSorted by cheapest first
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3

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.
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

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 July 1, 2026.

It’s optimal to fly from St. Louis to Key Largo in the evening. By choosing this option you can save up to 14% 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?

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 June 27, 2026.

Travelers seeking maximum savings on their St. Louis to Key Largo flight should consider departing on Tuesday 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 July 1, 2026.
Peruse reviews from past customers who have flown with Southwest,Delta, andUnited 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.

Overall

7.9

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
6.0
Good

Scott,Feb 2026

HOU - FLL

Delayed by 45 minutes leaving Houston, making a 3.5 hour layover that much longer.

Overall

7.9

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
6.0
Good

Scott,Feb 2026

HOU - FLL

Delayed by 45 minutes leaving Houston, making a 3.5 hour layover that much longer.

Overall

7.9

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
6.0
Good

Scott,Feb 2026

HOU - FLL

Delayed by 45 minutes leaving Houston, making a 3.5 hour layover that much longer.

Overall

7.9

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
6.0
Good

Scott,Feb 2026

HOU - FLL

Delayed by 45 minutes leaving Houston, making a 3.5 hour layover that much longer.

Overall

7.9

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
6.0
Good

Scott,Feb 2026

HOU - FLL

Delayed by 45 minutes leaving Houston, making a 3.5 hour layover that much longer.

Overall

7.9

Crew

8.6

Entertainment

7.5

Food

7.0

Boarding

8.1

Comfort

8.0

Reviews

1 / 20
6.0
Good

Scott,Feb 2026

HOU - FLL

Delayed by 45 minutes leaving Houston, making a 3.5 hour layover that much longer.

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.
  • What airport do you fly from for flights from St. Louis to Key Largo?

    For a flight from St. Louis to Key Largo, you will be flying from Lambert-St Louis. Lambert-St Louis (STL) is just 12.7 mi from the center of the city. Lambert-St Louis is the only St. Louis airport and it handles 2 outbound flights to Key Largo per day. 6 airlines have flights to Key Largo from Lambert-St Louis on a regular basis.

  • How popular is this St. Louis to Key Largo flight route?

  • How long is the flight from St. Louis to Key Largo?

    For as low as $297, Delta can have you in Key Largo from St. Louis in 2h 40m. The distance between St. Louis and Key Largo is about 1069 mi. Both multi-stop and nonstop flights can be found to your destination and back.

  • What are the cheapest airlines to fly from St. Louis to Key Largo one-way?

    For one-way options, check prices for Frontier. According to our data, you can fly for as low as $75. Users have also found prices from $89 and $100 on American Airlines and Delta, respectively.

  • What are the most reliable airlines from St. Louis to Key Largo?

    The top 3 most reliable airlines when flying from St. Louis to Key Largo are Envoy Air (100%), Royal Air Maroc (88%) and Qatar Airways (87%).

  • What are the cheapest flights from St. Louis to Key Largo?

    On average you can expect to pay $868 for a flight from St. Louis to Key Largo. The cheapest flight overall is $158 while the most popular route, (Lambert-St Louis - Miami) is currently priced at $171.

  • Can I find deals for flights from St. Louis to Key Largo that include hotel bookings?

    Yes. In addition to deals on St. Louis to Key Largo flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from St. Louis to Key Largo?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Key Largo.

  • Can I find deals for business class flights from St. Louis to Key Largo?

    Yes. Cheapflights offers flight deals from St. Louis to Key Largo by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

See more FAQs

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Alternative routes for St. Louis to Key Largo

See prices for flight routes from nearby airports that may be better suited for you.

Top 6 airlines flying from St. Louis to Key Largo

Discover the top 6 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 July 1, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$126Average$220FlexibilityNo cancel feeOn-time62%
United AirlinesCheapest$150Average$456FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$194Average$413FlexibilityNo cancel feeOn-time71%
DeltaCheapest$196Average$404FlexibilityNo cancel feeOn-timeN/A
JetBlueCheapest$220Average$408FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$245Average$454FlexibilityNo cancel feeOn-time63%

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