$172 Cheap Flights from St. Louis (STL) to Decatur (DEC)

View $172 flight on Wed, Dec 31, 2025Opens in a new window

Popular airlines from St. Louis Lambert Intl. Airport (STL) to Decatur, IL (DEC)

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Cheap Flights from St. Louis to Decatur (STL-DEC)

Prices were available within the past 7 days and start at $172 for one-way flights and $274 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

United
Mon, Nov 24 - Fri, Nov 28
STL
St. Louis
DEC
Decatur
$274 Roundtrip, found 1 day ago
$274
Roundtrip
found 1 day ago
Select United flight, departing Mon, Nov 24 from St. Louis to Decatur, returning Fri, Nov 28, priced at $274 found 1 day ago
United
Mon, Nov 24 - Tue, Dec 2
STL
St. Louis
DEC
Decatur
$289 Roundtrip, found 1 day ago
$289
Roundtrip
found 1 day ago
Select United flight, departing Mon, Nov 24 from St. Louis to Decatur, returning Tue, Dec 2, priced at $289 found 1 day ago
United
Mon, Nov 24 - Sun, Nov 30
STL
St. Louis
DEC
Decatur
$360 Roundtrip, found 1 day ago
$360
Roundtrip
found 1 day ago
Select United flight, departing Mon, Nov 24 from St. Louis to Decatur, returning Sun, Nov 30, priced at $360 found 1 day ago
United
Wed, Nov 26 - Fri, Nov 28
STL
St. Louis
DEC
Decatur
$364 Roundtrip, found 1 day ago
$364
Roundtrip
found 1 day ago
Select United flight, departing Wed, Nov 26 from St. Louis to Decatur, returning Fri, Nov 28, priced at $364 found 1 day ago
United
Wed, Nov 26 - Tue, Dec 2
STL
St. Louis
DEC
Decatur
$379 Roundtrip, found 1 day ago
$379
Roundtrip
found 1 day ago
Select United flight, departing Wed, Nov 26 from St. Louis to Decatur, returning Tue, Dec 2, priced at $379 found 1 day ago
United
Mon, Nov 24 - Mon, Dec 1
STL
St. Louis
DEC
Decatur
$399 Roundtrip, found 1 day ago
$399
Roundtrip
found 1 day ago
Select United flight, departing Mon, Nov 24 from St. Louis to Decatur, returning Mon, Dec 1, priced at $399 found 1 day ago
United
Fri, Nov 28 - Thu, Dec 4
STL
St. Louis
DEC
Decatur
$410 Roundtrip, found 1 day ago
$410
Roundtrip
found 1 day ago
Select United flight, departing Fri, Nov 28 from St. Louis to Decatur, returning Thu, Dec 4, priced at $410 found 1 day ago
United
Fri, Nov 28 - Tue, Dec 2
STL
St. Louis
DEC
Decatur
$425 Roundtrip, found 1 day ago
$425
Roundtrip
found 1 day ago
Select United flight, departing Fri, Nov 28 from St. Louis to Decatur, returning Tue, Dec 2, priced at $425 found 1 day ago
United
Wed, Nov 26 - Sun, Nov 30
STL
St. Louis
DEC
Decatur
$450 Roundtrip, found 1 day ago
$450
Roundtrip
found 1 day ago
Select United flight, departing Wed, Nov 26 from St. Louis to Decatur, returning Sun, Nov 30, priced at $450 found 1 day ago
Delta
Wed, Nov 26 - Mon, Dec 1
STL
St. Louis
DEC
Decatur
$797 Roundtrip, found 1 day ago
$797
Roundtrip
found 1 day ago
Select Delta flight, departing Wed, Nov 26 from St. Louis to Decatur, returning Mon, Dec 1, priced at $797 found 1 day ago

Frequently asked questions

How much does a flight from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC) cost?
Lock in a cheap one-way flight from $172 or cheap return flight from $274 from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to find our cheapest flight offers on this route.
What is the cheapest month to fly from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC)?
The cheapest month to fly from STL to DEC is November, when demand is low. Off-peak months are often when better flight deals are available between these airports.
What is the cheapest airline that flies from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC)?
Use the filter tool on Expedia to compare different airlines and find the most affordable carrier that'll fly you from STL to DEC. Then, sort your results by "Price (lowest to highest)" to pick up the best deal available.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC)?
You'll have to take a flight with a layover if you're traveling from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC). There are no daily direct flights on this route. However, simply filter your search to include one or more stops to find the best option for your trip.
What day of the week has the most flights from STL to DEC?
Friday is generally the busiest day for flights, while Tuesday is often the quietest.* Just remember that flight schedules can vary depending on a range of factors, such as the airline and season.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC)?
To land at Decatur Airport (DEC) without delays, select a flight that takes off from Lambert-St. Louis Intl. Airport (STL) before 3 PM. The likelihood of cancellations is 22% higher, on average, for departures after this hour.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
Is it cheaper to buy a plane ticket from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC) last-minute?
Holding off until just before your departure to book a flight from STL to DEC often results in higher prices. Although you may find some last-minute offers, they're not always guaranteed. Keep your travel plans flexible to maximize your chances of getting a bargain.
Is it cheaper to book a STL to DEC flight and hotel package?
Securing a STL to DEC flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the convenience of organizing your trip all in one place. Pick from our impressive range of accommodations and then add activities, car rentals and flights to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Decatur Airport (DEC)?
If you reserved your STL to DEC flight within the last 24 hours, you may be able to modify or cancel it without fees. Depending on the airline and the type of fare you purchased, additional charges may apply for changes after that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal for more details.

Travel information

Origin airport
Lambert-St. Louis Intl.
Destination airport
Decatur
Airlines serving
United
Roundtrip price
$274
Distance
109 mi

Book with confidence

St. Louis to Decatur Flights

The cheapest times to fly from St. Louis to Decatur

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from St. Louis to Decatur are during the month of November. You can find some of the cheapest flights from St. Louis to Decatur with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from St. Louis to Decatur

Sunday is one of the best days to book for cheap flights from St. Louis to Decatur: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from St. Louis to Decatur

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from St. Louis to Decatur in 2025. You can also book with separate airlines for your outbound and return journeys, from $172 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap St. Louis to Decatur flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your St. Louis to Decatur airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

St. Louis to Decatur Flights

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*Available to One Key members.