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$65+ Cheap flights from Key Largo, FL to St. Louis (STL)

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 1/22. Fares are subject to change and may not be available on all flights or dates of travel.
MIA — STL
Oct 16 — Oct 231
Thu 10/16
Thu 10/23
1 adult, Economy
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Cheapflights Tip: The best prices from Key Largo to Lambert-St Louis are usually found in October or September, booked 62 days in advance, depart on a Saturday or Friday and return on a Wednesday

Cheap flight deals from Key Largo to St. Louis

Keep the following information in mind while searching for Key Largo to St. Louis flight deals. Data was last updated September 16, 2025.

Round-trip from

$131
(American Airlines)

One-way from

$65
(American Airlines)

Popular in

March

Cheapest in

October

Average price

$289
From Key Largo to Lambert-St Louis
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One-way flight from Key Largo to Lambert-St Louis
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Highest demand for flights based on searches. 14% potential increase in price ($61 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($12 potential savings vs. average RT price).
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Average for round-trip flights in September 2025
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Find flight deals from Key Largo to St. Louis

Cheapest flights from Key Largo to St. Louis
Explore the most affordable flight options available from Key Largo to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on September 16, 2025.

This American Airlines deal was found by Cheapflights users on 9/13. 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 10/810:01 pmMIA - STL
Nonstop2h 55mAmerican Airlines
Sun 10/126:08 pmSTL - MIA
Nonstop2h 42mAmerican Airlines
Deal found 9/13$131
This American Airlines deal was found by Cheapflights users on 9/15. 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 11/58:28 pmMIA - STL
Nonstop2h 59mAmerican Airlines
Sun 11/165:15 amSTL - MIA
Nonstop2h 44mAmerican Airlines
Deal found 9/15$134
This Priceline deal was found by Cheapflights users on 9/14. 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 10/235:15 amMIA - STL
1 stop6h 22mFrontier
Sun 10/2610:17 amSTL - MIA
1 stop6h 16mFrontier
Deal found 9/14$148
This Frontier deal was found by Cheapflights users on 9/15. 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 10/25:30 amMIA - STL
1 stop10h 34mFrontier
Sun 10/54:00 pmSTL - MIA
1 stop7h 12mFrontier
Deal found 9/15$153
This American Airlines deal was found by Cheapflights users on 9/16. 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 10/1410:01 pmMIA - STL
Nonstop2h 55mAmerican Airlines
Tue 10/215:23 amSTL - MIA
Nonstop2h 47mAmerican Airlines
Deal found 9/16$169
This Frontier deal was found by Cheapflights users on 9/15. 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 9/225:30 amMIA - STL
1 stop10h 34mFrontier
Thu 9/254:00 pmSTL - MIA
1 stop7h 12mFrontier
Deal found 9/15$174
This Frontier deal was found by Cheapflights users on 9/15. 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 10/105:15 amMIA - STL
1 stop6h 22mFrontier
Sun 10/1210:17 amSTL - MIA
1 stop6h 16mFrontier
Deal found 9/15$182
This Frontier deal was found by Cheapflights users on 9/14. 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 10/235:15 amMIA - STL
1 stop6h 22mFrontier
Wed 11/57:45 pmSTL - MIA
1 stop9h 34mFrontier
Deal found 9/14$183
This Frontier deal was found by Cheapflights users on 9/14. 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 10/245:15 amMIA - STL
1 stop6h 01mFrontier
Mon 10/2710:18 amSTL - MIA
2 stops13h 16mFrontier
Deal found 9/14$186
This Frontier deal was found by Cheapflights users on 9/14. 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 9/295:30 amMIA - STL
1 stop10h 34mFrontier
Fri 10/37:55 pmSTL - MIA
2 stops14h 28mFrontier
Deal found 9/14$190
This American Airlines deal was found by Cheapflights users on 9/14. 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.
Thu 10/163:35 pmMIA - STL
Nonstop2h 53mAmerican Airlines
Sun 10/195:23 amSTL - MIA
Nonstop2h 47mAmerican Airlines
Deal found 9/14$191
This Mytrip deal was found by Cheapflights users on 9/16. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 9/266:00 amMIA - STL
1 stop28h 06mFrontier
Mon 9/294:00 pmSTL - MIA
1 stop7h 12mFrontier
Deal found 9/16$192

Cheapflights Fare Finder

 
Customize your flight search to find flights from Key Largo 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, Cheapflights users made 2,558,603 searches. Data last updated September 16, 2025.
Use the filters below to find and compare flights from Key Largo to St. Louis that are best for you.

Fly from

Key Largo

Fly to

St. Louis

Route

Depart

Return

Price

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Thu 10/23

10:01 pm-11:56 pm

Nonstop2h 55m

Lambert-St Louis

Sun 10/26

6:08 pm-9:50 pm

Nonstop2h 42m

$131

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 10/8

10:01 pm-11:56 pm

Nonstop2h 55m

Lambert-St Louis

Sun 10/12

6:08 pm-9:50 pm

Nonstop2h 42m

$131

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Thu 10/23

3:35 pm-5:28 pm

Nonstop2h 53m

Lambert-St Louis

Wed 11/5

5:15 am-8:59 am

Nonstop2h 44m

$191

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 11/5

8:28 pm-10:27 pm

Nonstop2h 59m

Lambert-St Louis

Sun 11/16

5:15 am-8:59 am

Nonstop2h 44m

$195

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 10/15

7:10 am-12:35 pm

1 stop6h 25m

Lambert-St Louis

Tue 10/21

7:05 am-3:30 pm

1 stop7h 25m

$197

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 10/8

10:40 am-3:55 pm

1 stop6h 15m

Lambert-St Louis

Sun 10/12

6:00 am-1:11 pm

1 stop6h 11m

$197

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Mon 9/29

5:30 am-3:04 pm

1 stop10h 34m

Lambert-St Louis

Wed 10/1

7:55 pm-10:40 am

2 stops13h 45m

$201

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 10/15

10:01 pm-11:56 pm

Nonstop2h 55m

Lambert-St Louis

Fri 10/17

6:08 pm-9:50 pm

Nonstop2h 42m

$204

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Thu 10/23

6:43 pm-9:07 am

2 stops15h 24m

Lambert-St Louis

Sun 10/26

10:17 am-5:33 pm

1 stop6h 16m

$211

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Sat 11/1

5:45 am-7:35 am

Nonstop2h 50m

Lambert-St Louis

Mon 11/3

12:45 pm-8:25 pm

1 stop6h 40m

$214

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/14

Showing 1-10 of 20 results
1
2

Best time to book a flight from Key Largo to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Key Largo 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 Key Largo to St. Louis

How far ahead should I book a flight from Key Largo to St. Louis?

Use this chart to determine the optimal time to book a round-trip flight from Key Largo to St. Louis. Price data was last updated on September 12, 2025.

The price you pay for your flight from Key Largo to St. Louis may vary depending on when you book. For the best chance of a lower fare, look to book 62 days in advance of your trip. Fares are likely to increase a fortnight or so before your departure date.

What is the cheapest month to book a flight from Key Largo to St. Louis?

Currently, August is the cheapest month in which you can book a flight from Key Largo to St. Louis (average of $311). Flying from Key Largo to St. Louis in March is currently the most expensive (average of $356). 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 KE9 to STL?

Find hourly flight availability from Key Largo to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated September 16, 2025.

When flying from Key Largo to St. Louis, the time of day you decide to fly out makes little to no difference towards the overall price you’ll pay on tickets.

What is the cheapest day to fly from Key Largo to St. Louis?

Use this chart to determine the cheapest time to fly round-trip from Key Largo to St. Louis. Price data was last updated on December 16, 2024.

Travelers seeking maximum savings on their Key Largo to St. Louis flight should consider departing on Friday mornings when fares are most often at their lowest. Wednesday at noon flights should be avoided if possible as fares are typically the most expensive at this time.

Weekly flight availability from Key Largo to St. Louis

Explore weekly flight availability from Key Largo to St. Louis. 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 September 16, 2025.

The most flights from KE9 to STL are scheduled on a Monday (4 on average). You will have fewer flight options on Sunday, which is when the least amount of flights are scheduled (2 on average).

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. 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 St. Louis. Reviews last updated September 16, 2025.
See what other customers who have flown with Southwest, Delta, and American Airlines from Key Largo to St. Louis have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Food

7.0

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Southwest
8.0
Very good
4,242 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Food

7.0

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Delta
8.0
Very good
7,957 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Food

7.0

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Food

7.0

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Spirit Airlines
6.3
Okay
8,019 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Food

7.0

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
Frontier
5.8
Fair
3,174 reviews
Southwest
8.0
Very good
4,242 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Entertainment

7.5

Food

7.0

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

Related info for your journey

Find useful and relevant information for your journey from Key Largo to St. Louis. 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 into for flights to St. Louis from Key Largo?

    If you book a flight to St. Louis from Key Largo, you will be flying to Lambert-St Louis, which is the city’s only airport. Lambert-St Louis (STL) is located 12.7 mi from the center of St. Louis. There are 3 flights from Key Largo to Lambert-St Louis per day from 5 different airlines.

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

    Flights from Key Largo to Lambert-St Louis have been viewed 15 times in the past calendar month.

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

    Airlines like American Airlines fly from Key Largo to St. Louis in about 2h 55m. The time it takes to get you to your destination is usually consistent. The distance from Key Largo to St. Louis is about 1069 mi. Generally, flights for this route are nonstop.

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

    Before booking your flight to St. Louis from Key Largo, check out the most reliable airlines to get you to your destination on time: Envoy Air (100%), American Airlines (73%), Southwest( 67%).

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

    Looking at all options, your cheapest flight can be booked for $114. While the most popular route (Miami - Lambert-St Louis) can be booked for $131 on average, our data indicates $272 when flying from Key Largo to St. Louis.

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

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

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

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

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

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

  • What is the cheapest month to book a flight from Key Largo to St. Louis?

    Currently, August is the cheapest month in which you can book a flight from Key Largo to St. Louis (average of $311). Flying from Key Largo to St. Louis in March is currently the most expensive (average of $356). 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.

See more FAQs

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Edwardsville
O'Fallon
Fairview Heights
Maryland Heights
Collinsville
Eureka
Glencoe
St. Peters
Chesterfield
Alton
Farmington
Festus

Browse thousands of different options on Cheapflights for your next trip

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Top 5 airlines flying from Key Largo to St. Louis

Discover the top 5 airlines that operate flights from Key Largo to St. Louis. 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 September 16, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$86Average$170FlexibilityNo cancel feeOn-time65%
FrontierCheapest$128Average$283FlexibilityNo cancel feeOn-time62%
SouthwestCheapest$186Average$373FlexibilityNo cancel feeOn-time63%
DeltaCheapest$196Average$347FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$229Average$389FlexibilityNo cancel feeOn-time71%

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