HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
Key Largo

$55+ 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 4/7. Fares are subject to change and may not be available on all flights or dates of travel.
STL — MIA
feb. 4 — feb. 111
mar. 2/4
mar. 2/11
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

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.

The best prices from Lambert-St Louis to Key Largo are usually found in September or August, booked 63 days in advance, depart on a Friday or Sunday and return on a Saturday

Cheap flight deals from St. Louis to Key Largo

Discover tips and strategies to find the most affordable flight options for your journey from St. Louis (STL) to Key Largo (KE9). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated enero 30, 2025.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$292
(American Airlines)

One-way from

$55
(Frontier)

Popular in

March

Cheapest in

September

Average price

$389
Provider with most accurate pricing for Lambert-St Louis-Miami flight deals.
Search Deals
Provider most trusted by Cheapflights users for Lambert-St Louis-Miami flights.
Search Deals
From Lambert-St Louis to Key Largo
Search Deals
One-way flight from Lambert-St Louis to Key Largo
Search Deals
Highest demand for flights based on searches. 8% potential increase in price ($35 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 2% potential price decrease ($11 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in January 2025
Search Deals

Find 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 enero 30, 2025.

This Delta deal was found by Cheapflights users on 1/29. 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 Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 2/206:06 amSTL - MIA
1 stop11h 48mDelta
mié. 2/267:00 amMIA - STL
1 stop5h 46mDelta
Deal found 1/29$295
This Southwest deal was found by Cheapflights users on 1/29. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 4/196:40 pmSTL - MIA
Nonstop2h 40mSouthwest
mié. 4/238:30 amMIA - STL
2 stops10h 15mSouthwest
Deal found 1/29$297
This Mytrip deal was found by Cheapflights users on 1/29. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 2/274:00 pmSTL - MIA
2 stops30h 29mMultiple Airlines
jue. 3/69:53 pmMIA - STL
3 stops19h 52mMultiple Airlines
Deal found 1/29$299
This Booking.com deal was found by Cheapflights users on 1/30. 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 Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
vie. 2/147:09 pmSTL - MIA
1 stop9h 07mFrontier
mar. 2/186:25 amMIA - STL
1 stop27h 51mFrontier
Deal found 1/30$300
This American Airlines deal was found by Cheapflights users on 1/29. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
jue. 2/275:13 amSTL - MIA
Nonstop2h 56mAmerican Airlines
jue. 3/69:50 pmMIA - STL
Nonstop2h 56mAmerican Airlines
Deal found 1/29$301
This Mytrip deal was found by Cheapflights users on 1/29. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
dom. 3/95:38 pmSTL - MIA
2 stops26h 20mSpirit Airlines
vie. 3/142:32 pmMIA - STL
2 stops19h 37mSpirit Airlines
Deal found 1/29$316
This United Airlines deal was found by Cheapflights users on 1/29. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
sáb. 3/18:40 amSTL - MIA
1 stop8h 14mUnited Airlines
mié. 3/126:00 amMIA - STL
2 stops10h 31mUnited Airlines
Deal found 1/29$387

Find flights from St. Louis to Key Largo within your budget

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 enero 30, 2025.

Fly from

Any airport

Fly to

Any airport

Route

Depart

Return

Price

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

sáb. 4/12

1:48 pm-8:47 pm

1 stop5h 59m

Miami

jue. 4/17

8:16 pm-10:21 pm

Nonstop3h 05m

$292

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

jue. 2/20

6:06 am-6:54 pm

1 stop11h 48m

Miami

mié. 2/26

7:00 am-11:46 am

1 stop5h 46m

$295

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

sáb. 4/19

6:40 pm-10:20 pm

Nonstop2h 40m

Miami

mié. 4/23

8:30 am-5:45 pm

2 stops10h 15m

$297

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

jue. 2/27

4:00 pm-11:29 pm

2 stops30h 29m

Miami

jue. 3/6

9:53 pm-4:45 pm

3 stops19h 52m

$299

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

vie. 2/14

7:09 pm-5:16 am

1 stop9h 07m

Miami

mar. 2/18

6:25 am-9:16 am

1 stop27h 51m

$300

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

dom. 3/9

5:38 pm-8:58 pm

2 stops26h 20m

Miami

vie. 3/14

2:32 pm-9:09 am

2 stops19h 37m

$316

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

sáb. 3/1

10:55 am-5:54 pm

1 stop5h 59m

Miami

jue. 3/6

6:00 am-3:31 pm

2 stops10h 31m

$387

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

lun. 4/7

6:51 pm-5:21 am

1 stop9h 30m

$55

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

mar. 3/4

4:00 pm-8:29 am

2 stops15h 29m

$81

St. LouisMiami

STL - MIA

STLMIA

Lambert-St Louis

mar. 4/22

6:09 pm-9:54 pm

Nonstop2h 45m

$119

Flights are sorted by cheapest round-trip flights first.

Deals found on 1/30

Showing 1-10 of 15 results
1
2

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.

Travel insights for flights from St. Louis to Key Largo

Get recent, data-driven insights about flights from St. Louis to Key Largo including ideal travel times, pricing trends, and more.

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 January 24, 2025.

To ensure you get the cheapest price possible for a flight from St. Louis to Key Largo, you should look to book at least 63 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, September is the cheapest month in which you can book a flight from St. Louis to Key Largo (average of $231). Flying from St. Louis to Key Largo in March is currently the most expensive (average of $289). 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 enero 30, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from St. Louis to Key Largo as you normally would.

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 December 16, 2024.

Travelers seeking maximum savings on their St. Louis to Key Largo flight should consider departing on Monday evenings when fares are most often at their lowest. Tuesday afternoons 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 enero 30, 2025.

The most flights from STL to KE9 are scheduled on a Wednesday (6 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (2 on average).

Rainfall in Key Largo by month

Plan your trip to Key Largo by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in Key Largo ranges from 1.6 - 9.9 inches per month. September is typically the wettest month, when rainfall can reach 9.9 in. January is typically the driest time to visit Key Largo when rainfall is around 1.6 in.

Temperature in Key Largo by month

Plan your trip to Key Largo by taking into account the average temperature totals by month.

If weather is an important factor for your trip to Key Largo, 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 84.2 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 68.0 F).

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 enero 30, 2025.
Peruse reviews from past customers who have flown with Southwest, Delta and United Airlines from St. Louis to Key Largo to help guide your decision. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.1
Very good
4,585 reviews

Boarding

8.2

Entertainment

7.7

Food

7.1

Crew

8.7

Overall

8.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Southwest
8.1
Very good
4,585 reviews
Southwest
8.1
Very good
4,585 reviews

Boarding

8.2

Entertainment

7.7

Food

7.1

Crew

8.7

Overall

8.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Delta
8.0
Very good
8,454 reviews
Southwest
8.1
Very good
4,585 reviews

Boarding

8.2

Entertainment

7.7

Food

7.1

Crew

8.7

Overall

8.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

United Airlines
7.4
Good
8,913 reviews
Southwest
8.1
Very good
4,585 reviews

Boarding

8.2

Entertainment

7.7

Food

7.1

Crew

8.7

Overall

8.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

American Airlines
7.2
Good
10,000 reviews
Southwest
8.1
Very good
4,585 reviews

Boarding

8.2

Entertainment

7.7

Food

7.1

Crew

8.7

Overall

8.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

Sun Country Air
7.0
Good
386 reviews
Southwest
8.1
Very good
4,585 reviews

Boarding

8.2

Entertainment

7.7

Food

7.1

Crew

8.7

Overall

8.1

Comfort

8.1

Reviews

1 / 20

6.0
Good

Lauren,Dec 2024

MCI - DCA

We BARELY made the connection and when we got onboard we were treated like disobedient children who should have arrived earlier because we had to ask other passengers to move so we could sit with our kids. The flight attendants on the first flight were nice but the second one, they were snippy and fairly rude.

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 3 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?

    The Lambert-St Louis to Key Largo flight path was viewed by 8 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • 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 $55. Users have also found prices from $81 and $119 on Spirit Airlines and American Airlines, 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 Southwest (82%), Qatar Airways (76%) and American Airlines (73%).

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

    On average you can expect to pay $420 for a flight from St. Louis to Key Largo. The cheapest flight overall is $89 while the most popular route, (Lambert-St Louis - Miami) is currently priced at $194.

  • 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.

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

    Currently, September is the cheapest month in which you can book a flight from St. Louis to Key Largo (average of $231). Flying from St. Louis to Key Largo in March is currently the most expensive (average of $289). 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

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for St. Louis to Key Largo

See prices for flight routes from nearby airports that may be better suited for you.
St. Louis to Orlando flights
St. Louis to Miami flights
Kansas City to Orlando flights
Kansas City to Miami flights
Kansas City to Tampa flights
St. Louis to Fort Lauderdale flights
St. Louis to Tampa flights
St. Louis to Fort Myers flights
Kansas City to Fort Lauderdale flights
Kansas City to Fort Myers flights
Kansas City to Pensacola flights
St. Louis to West Palm Beach flights
Kansas City to Sarasota flights
Springfield to Orlando flights
St. Louis to Pensacola flights
Kansas City to Key West flights
St. Louis to Key West flights
St. Louis to Sarasota flights
St. Louis to Panama City flights
Springfield to West Palm Beach flights
St. Louis to Jacksonville flights
Springfield to Tampa flights
Kansas City to West Palm Beach flights
Springfield to Fort Lauderdale flights
Kansas City to Panama City flights
Springfield to Miami flights
Springfield to Jacksonville flights
St. Louis to Valparaiso flights
Kansas City to Jacksonville flights
St. Louis to Daytona Beach flights
Kansas City to Valparaiso flights
St. Louis to Melbourne flights
Springfield to Sarasota flights
Springfield to Key West flights
Kansas City to St Petersburg flights
Joplin to Sarasota flights
Joplin to Jacksonville flights
Springfield to St Petersburg flights
Springfield to Pensacola flights
Springfield to Fort Myers flights
Joplin to Tampa flights
Kansas City to Gainesville flights
Kansas City to Daytona Beach flights
Joplin to Miami flights
St. Louis to Tallahassee flights
St. Louis to Gainesville flights
Springfield to Panama City flights
Joplin to Pensacola flights
Kansas City to Orlando Sanford Intl flights
Kansas City to Punta Gorda flights

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 enero 30, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$69Average$147FlexibilityNo cancel feeOn-time65%
FrontierCheapest$139Average$235FlexibilityNo cancel feeOn-time62%
DeltaCheapest$208Average$424FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$237Average$411FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$283Average$451FlexibilityNo cancel feeOn-time63%
United AirlinesCheapest$287Average$499FlexibilityNo cancel feeOn-time69%
100% Free
Cheapflights is completely free to use, so you can start saving the moment you arrive.
Book with Flexibility
Our users can plan ahead with confidence and find flights with no change fees
Travel Smart
Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.