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$103+ 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 6/12. Fares are subject to change and may not be available on all flights or dates of travel.
MIA — STL
abr. 7 — abr. 141
lun. 4/7
lun. 4/14
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 July, booked 48 days in advance, depart on a Thursday or Tuesday and return on a Friday

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 abril 2, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$198
(Frontier)

One-way from

$103
(Cheapflightsfares)

Popular in

March

Cheapest in

September

Average price

$371
Provider with most accurate pricing for Miami-Lambert-St Louis flight deals.
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Provider most trusted by Cheapflights users for Miami-Lambert-St Louis flights.
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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. 13% potential increase in price ($59 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 April 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 abril 2, 2025.

This Frontier deal was found by Cheapflights users on 4/1. 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.
jue. 5/16:00 amMIA - STL
1 stop10h 07mFrontier
vie. 5/26:53 pmSTL - MIA
1 stop9h 29mFrontier
Deal found 4/1$198
This FlightHub deal was found by Cheapflights users on 4/1. 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.
jue. 11/67:58 pmMIA - STL
1 stop12h 51mSpirit Airlines
dom. 11/98:44 amSTL - MIA
1 stop9h 09mSpirit Airlines
Deal found 4/1$205
This Delta deal was found by Cheapflights users on 4/1. 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.
mar. 4/226:00 amMIA - STL
1 stop4h 36mDelta
mar. 4/295:32 pmSTL - MIA
1 stop6h 16mDelta
Deal found 4/1$239
This American Airlines deal was found by Cheapflights users on 4/1. 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.
mar. 4/228:34 amMIA - STL
1 stop7h 19mAmerican Airlines
mar. 4/296:09 pmSTL - MIA
Nonstop2h 45mAmerican Airlines
Deal found 4/1$253
This Southwest deal was found by Cheapflights users on 4/1. 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.
jue. 4/242:50 pmMIA - STL
Nonstop2h 55mSouthwest
lun. 4/286:55 amSTL - MIA
1 stop8h 05mSouthwest
Deal found 4/1$289
This Mytrip deal was found by Cheapflights users on 4/1. 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.
jue. 5/11:53 pmMIA - STL
2 stops22h 38mMultiple Airlines
lun. 5/512:15 pmSTL - MIA
2 stops33h 57mMultiple Airlines
Deal found 4/1$295
This United Airlines deal was found by Cheapflights users on 4/1. 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.
jue. 8/284:55 pmMIA - STL
1 stop6h 13mUnited Airlines
dom. 8/3111:20 amSTL - MIA
2 stops9h 55mUnited Airlines
Deal found 4/1$352

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 abril 2, 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

jue. 5/1

6:00 am-3:07 pm

1 stop10h 07m

Lambert-St Louis

vie. 5/2

6:53 pm-5:22 am

1 stop9h 29m

$198

MiamiSt. Louis

MIA - STL

MIASTL

Miami

mar. 4/22

6:00 am-9:36 am

1 stop4h 36m

Lambert-St Louis

mar. 4/29

5:32 pm-12:48 am

1 stop6h 16m

$239

MiamiSt. Louis

MIA - STL

MIASTL

Miami

mar. 4/22

8:34 am-2:53 pm

1 stop7h 19m

Lambert-St Louis

mar. 4/29

6:09 pm-9:54 pm

Nonstop2h 45m

$253

MiamiSt. Louis

MIA - STL

MIASTL

Miami

jue. 4/24

2:50 pm-4:45 pm

Nonstop2h 55m

Lambert-St Louis

lun. 4/28

6:55 am-4:00 pm

1 stop8h 05m

$289

MiamiSt. Louis

MIA - STL

MIASTL

Miami

jue. 5/1

1:53 pm-11:31 am

2 stops22h 38m

Lambert-St Louis

lun. 5/5

12:15 pm-11:12 pm

2 stops33h 57m

$295

MiamiSt. Louis

MIA - STL

MIASTL

Miami

jue. 8/28

4:55 pm-10:08 pm

1 stop6h 13m

Lambert-St Louis

dom. 8/31

11:20 am-10:15 pm

2 stops9h 55m

$352

MiamiSt. Louis

MIA - STL

MIASTL

Miami

vie. 6/20

9:08 am-3:22 pm

1 stop7h 14m

Lambert-St Louis

vie. 6/27

4:17 pm-9:58 am

2 stops16h 41m

$356

MiamiSt. Louis

MIA - STL

MIASTL

Miami

mar. 6/3

6:21 pm-9:49 am

2 stops16h 28m

Lambert-St Louis

jue. 6/5

4:23 pm-5:21 pm

2 stops23h 58m

$838

MiamiSt. Louis

MIA - STL

MIASTL

Miami

jue. 6/12

9:08 am-3:22 pm

1 stop7h 14m

$103

MiamiSt. Louis

MIA - STL

MIASTL

Miami

vie. 5/16

6:00 am-9:59 am

1 stop28h 59m

$105

Flights are sorted by cheapest round-trip flights first.

Deals found on 4/1

Showing 1-10 of 16 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 March 28, 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 48 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 abril 2, 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 Sunday at noon 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.

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 abril 2, 2025.
See what other customers who have flown with Alaska Airlines, Southwest and Delta 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.
Alaska Airlines
8.0
Very good
9,823 reviews

Crew

8.5

Comfort

7.9

Entertainment

7.1

Food

7.1

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Alaska Airlines
8.0
Very good
9,823 reviews
Alaska Airlines
8.0
Very good
9,823 reviews

Crew

8.5

Comfort

7.9

Entertainment

7.1

Food

7.1

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Southwest
8.0
Very good
4,275 reviews
Alaska Airlines
8.0
Very good
9,823 reviews

Crew

8.5

Comfort

7.9

Entertainment

7.1

Food

7.1

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
Delta
8.0
Very good
7,897 reviews
Alaska Airlines
8.0
Very good
9,823 reviews

Crew

8.5

Comfort

7.9

Entertainment

7.1

Food

7.1

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
United Airlines
7.4
Good
8,616 reviews
Alaska Airlines
8.0
Very good
9,823 reviews

Crew

8.5

Comfort

7.9

Entertainment

7.1

Food

7.1

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
9,823 reviews

Crew

8.5

Comfort

7.9

Entertainment

7.1

Food

7.1

Overall

8.0

Boarding

8.2

Reviews

1 / 20
10.0
Excellent

Cheri,Jan 2025

FAT - SEA

Very friendly. I really liked that they had water for us in cartons not plastic. Impressed with Alaska Airlines, First time I had flown them

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 2 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 Spirit Airlines, which is currently one of the cheapest options available, starting at $103. Frontier flights start at $105 while deals on Delta start at $110 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: Finnair (93%), Envoy Air (90%), Qatar Airways( 85%).

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

    Looking at all options, your cheapest flight can be booked for $163. While the most popular route (Miami - Lambert-St Louis) can be booked for $200 on average our data indicates $382 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
Fenton
Maryland Heights
Fairview Heights
Collinsville
Wentzville
Eureka
St. Peters
Festus
Glencoe
Alton
Farmington
Chesterfield

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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 abril 2, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$85Average$152FlexibilityNo cancel feeOn-time65%
FrontierCheapest$128Average$243FlexibilityNo cancel feeOn-time62%
DeltaCheapest$199Average$401FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$209Average$359FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$249Average$400FlexibilityNo cancel feeOn-time63%

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