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$109+ 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 10/15. Fares are subject to change and may not be available on all flights or dates of travel.
MIA — STL
Jun 17 — Jun 241
Tue 6/17
Tue 6/24
1 adult, Economy
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Cheapflights Tip: The best prices from Key Largo to Lambert-St Louis are usually found in September or October, booked 83 days in advance, depart on a Friday or Tuesday 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 June 12, 2025.

Round-trip from

$175
(Cheapflightsfares)

One-way from

$111
(Delta)

Popular in

March

Cheapest in

September

Average price

$365
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. 12% potential increase in price ($51 potential increase over avg. RT price).
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Cheapest flight prices on average. 3% potential price decrease ($11 potential savings vs. average RT price).
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Average for round-trip flights in June 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 June 12, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 6/10. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/47:58 pmMIA - STL
1 stop12h 51mSpirit Airlines
Sun 9/78:44 amSTL - MIA
1 stop9h 09mSpirit Airlines
Deal found 6/10$175
This American Airlines deal was found by Cheapflights users on 6/11. 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 8/1310:09 pmMIA - STL
Nonstop2h 50mAmerican Airlines
Tue 8/195:22 amSTL - MIA
Nonstop2h 48mAmerican Airlines
Deal found 6/11$181
This Delta deal was found by Cheapflights users on 6/10. 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 8/68:02 amMIA - STL
1 stop5h 32mDelta
Sun 8/107:00 amSTL - MIA
1 stop5h 07mDelta
Deal found 6/10$201
This Southwest deal was found by Cheapflights users on 6/11. 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 8/132:50 pmMIA - STL
Nonstop2h 50mSouthwest
Tue 8/192:15 pmSTL - MIA
1 stop6h 00mSouthwest
Deal found 6/11$208
This FlightHub deal was found by Cheapflights users on 6/10. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 7/186:00 amMIA - STL
1 stop28h 11mMultiple Airlines
Sun 7/2010:47 amSTL - MIA
1 stop22h 24mMultiple Airlines
Deal found 6/10$228
This FlightHub deal was found by Cheapflights users on 6/11. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/316:00 amMIA - STL
1 stop28h 11mFrontier
Sun 8/32:36 pmSTL - MIA
1 stop5h 03mFrontier
Deal found 6/11$235
This United Airlines deal was found by Cheapflights users on 6/11. 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 8/51:30 pmMIA - STL
2 stops10h 15mUnited Airlines
Thu 8/78:00 amSTL - MIA
1 stop6h 14mUnited Airlines
Deal found 6/11$272

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 June 12, 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 9/4

7:58 pm-7:49 am

1 stop12h 51m

Lambert-St Louis

Sun 9/7

8:44 am-6:53 pm

1 stop9h 09m

$175

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 8/13

10:09 pm-11:59 pm

Nonstop2h 50m

Lambert-St Louis

Tue 8/19

5:22 am-9:10 am

Nonstop2h 48m

$181

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 8/6

8:02 am-12:34 pm

1 stop5h 32m

Lambert-St Louis

Sun 8/10

7:00 am-1:07 pm

1 stop5h 07m

$201

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 8/13

2:50 pm-4:40 pm

Nonstop2h 50m

Lambert-St Louis

Tue 8/19

2:15 pm-9:15 pm

1 stop6h 00m

$208

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Fri 7/18

6:00 am-9:11 am

1 stop28h 11m

Lambert-St Louis

Sun 7/20

10:47 am-10:11 am

1 stop22h 24m

$228

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Thu 7/31

6:00 am-9:11 am

1 stop28h 11m

Lambert-St Louis

Sun 8/3

2:36 pm-8:39 pm

1 stop5h 03m

$235

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Tue 8/5

1:30 pm-10:45 pm

2 stops10h 15m

Lambert-St Louis

Thu 8/7

8:00 am-3:14 pm

1 stop6h 14m

$272

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 10/15

10:30 am-12:30 pm

Nonstop3h 00m

$109

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 7/2

6:00 am-9:15 am

1 stop4h 15m

$111

MiamiSt. Louis

MIA - STL

MIASTL

Miami

Wed 7/9

2:23 pm-9:52 am

2 stops20h 29m

$113

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/10

Showing 1-10 of 15 results
1
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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 June 9, 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 83 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 June 12, 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 June 23, 2024.

Travelers seeking maximum savings on their Key Largo to St. Louis flight should consider departing on Tuesday evenings 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 June 12, 2025.

The most flights from KE9 to STL are scheduled on a Wednesday (5 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (3 on average).

Rainfall in St. Louis by month

Plan your trip to St. Louis by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in St. Louis ranges from 2.2 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. February is typically the driest time to visit St. Louis when rainfall is around 2.2 in.

Temperature in St. Louis by month

Plan your trip to St. Louis by taking into account the average temperature totals by month.

If weather is an important factor for your trip to St. Louis, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

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 June 12, 2025.
See what other customers who have flown with Southwest, Delta and United Airlines from Key Largo to St. Louis have to say. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,287 reviews

Boarding

8.2

Comfort

8.0

Food

7.1

Overall

8.0

Entertainment

7.6

Crew

8.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Southwest
8.0
Very good
4,287 reviews
Southwest
8.0
Very good
4,287 reviews

Boarding

8.2

Comfort

8.0

Food

7.1

Overall

8.0

Entertainment

7.6

Crew

8.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Delta
8.0
Very good
7,950 reviews
Southwest
8.0
Very good
4,287 reviews

Boarding

8.2

Comfort

8.0

Food

7.1

Overall

8.0

Entertainment

7.6

Crew

8.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
United Airlines
7.4
Good
8,790 reviews
Southwest
8.0
Very good
4,287 reviews

Boarding

8.2

Comfort

8.0

Food

7.1

Overall

8.0

Entertainment

7.6

Crew

8.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,287 reviews

Boarding

8.2

Comfort

8.0

Food

7.1

Overall

8.0

Entertainment

7.6

Crew

8.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Spirit Airlines
6.3
Okay
8,052 reviews
Southwest
8.0
Very good
4,287 reviews

Boarding

8.2

Comfort

8.0

Food

7.1

Overall

8.0

Entertainment

7.6

Crew

8.6

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.

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 4 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 4 times in the past calendar month.

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

    To fly one-way, consider booking your trip with Delta, which is currently one of the cheapest options available, starting at $111. Spirit Airlines flights start at $113 while deals on Frontier start at $114 one-way.

  • 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: Southwest (70%), American Airlines (53%), Qatar Airways( 52%).

  • 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 $175 on average our data indicates $329 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 Key Largo?

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

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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 June 12, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$83Average$157FlexibilityNo cancel feeOn-time65%
FrontierCheapest$128Average$257FlexibilityNo cancel feeOn-time62%
DeltaCheapest$199Average$366FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$209Average$366FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$258Average$400FlexibilityNo cancel feeOn-time63%

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