$233 Cheap Flights from Watertown (ATY) to St. Louis (STL)

View $233 flight on Fri, Dec 12, 2025Opens in a new window

Popular airlines from Watertown, SD (ATY-Watertown Regional) to St. Louis Lambert Intl. Airport (STL)

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Cheap Flights from Watertown to St. Louis (ATY-STL)

Prices were available within the past 7 days and start at $233 for one-way flights and $234 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Delta
Wed, Jan 28 - Mon, Feb 2
ATY
Watertown
STL
St. Louis
$234 Roundtrip, just found
$234
Roundtrip
just found
Select Delta flight, departing Wed, Jan 28 from Watertown to St. Louis, returning Mon, Feb 2, priced at $234 just found
Delta
Wed, Jan 28 - Sat, Feb 7
ATY
Watertown
STL
St. Louis
$244 Roundtrip, just found
$244
Roundtrip
just found
Select Delta flight, departing Wed, Jan 28 from Watertown to St. Louis, returning Sat, Feb 7, priced at $244 just found
Delta
Tue, Feb 3 - Tue, Feb 10
ATY
Watertown
STL
St. Louis
$249 Roundtrip, just found
$249
Roundtrip
just found
Select Delta flight, departing Tue, Feb 3 from Watertown to St. Louis, returning Tue, Feb 10, priced at $249 just found
Delta
Wed, Jan 28 - Sat, Jan 31
ATY
Watertown
STL
St. Louis
$259 Roundtrip, just found
$259
Roundtrip
just found
Select Delta flight, departing Wed, Jan 28 from Watertown to St. Louis, returning Sat, Jan 31, priced at $259 just found
Delta
Fri, Nov 21 - Sat, Nov 22
ATY
Watertown
STL
St. Louis
$264 Roundtrip, found 1 day ago
$264
Roundtrip
found 1 day ago
Select Delta flight, departing Fri, Nov 21 from Watertown to St. Louis, returning Sat, Nov 22, priced at $264 found 1 day ago
Delta
Sat, Jan 31 - Sun, Feb 1
ATY
Watertown
STL
St. Louis
$289 Roundtrip, just found
$289
Roundtrip
just found
Select Delta flight, departing Sat, Jan 31 from Watertown to St. Louis, returning Sun, Feb 1, priced at $289 just found
Delta
Sat, Jan 31 - Sun, Feb 1
ATY
Watertown
STL
St. Louis
$299 Roundtrip, just found
$299
Roundtrip
just found
Select Delta flight, departing Sat, Jan 31 from Watertown to St. Louis, returning Sun, Feb 1, priced at $299 just found
Delta
Fri, Nov 21 - Fri, Nov 28
ATY
Watertown
STL
St. Louis
$304 Roundtrip, found 1 day ago
$304
Roundtrip
found 1 day ago
Select Delta flight, departing Fri, Nov 21 from Watertown to St. Louis, returning Fri, Nov 28, priced at $304 found 1 day ago
Delta
Thu, Nov 27 - Fri, Nov 28
ATY
Watertown
STL
St. Louis
$314 Roundtrip, found 1 day ago
$314
Roundtrip
found 1 day ago
Select Delta flight, departing Thu, Nov 27 from Watertown to St. Louis, returning Fri, Nov 28, priced at $314 found 1 day ago
United
Fri, Jan 30 - Sun, Feb 1
ATY
Watertown
STL
St. Louis
$395 Roundtrip, just found
$395
Roundtrip
just found
Select United flight, departing Fri, Jan 30 from Watertown to St. Louis, returning Sun, Feb 1, priced at $395 just found

Alternative airports near St. Louis

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $249
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $249

Frequently asked questions

How much does a flight from Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL) cost?
Get a cheap one-way flight from $233 or cheap return flight from $234 from Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL) 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 Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL)?
Flying in January may help you find better deals, as it's the cheapest month for flights between ATY and STL. You'll usually find the lowest prices during off-peak months.
What is the cheapest airline that flies from Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL)?
Use the filter tool on Expedia to compare airlines and find the most affordable carrier that'll fly you from ATY to STL. Then, sort your results by "Price (lowest to highest)" to score a good deal.
How many flights per day from Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL)?
There aren't any daily direct flights departing from Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL). But you can book flights with layovers. Filter your search results on Expedia to include one or two stops, and you'll be soaring above the clouds before you know it.
What day of the week has the most flights from ATY to STL?
You'll usually find Tuesday the quietest day for flights, while Fridays tend to be the busiest.* However this can vary from season to season and during peak travel times or public holidays.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL)?
Select a flight from Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL) that leaves before 3 PM to reduce the likelihood of delays. Departures after this time have a 22% higher chance of being canceled, on average.**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 Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL) last-minute?
Last-minute bookings from ATY to STL are usually more expensive. To lock in the lowest prices, start searching for flights as early as possible. That being said, if you can play around with your travel dates, it's possible to score a cheap fare right before you leave.
Is it cheaper to book an ATY to STL flight and hotel package?
You can save money by securing an ATY to STL flight and hotel package compared to booking separately. In fact, travelers could save hundreds of dollars by bundling with Expedia. And it's simple to manage it all in one place. Once you've chosen your ideal accommodations and flights, you can add extras such as car rentals, tours and activities.
Can I cancel or change the date of my flight from Watertown Regional Airport (ATY) to Lambert-St. Louis Intl. Airport (STL)?
It's usually possible to reschedule or cancel your ATY to STL flight. However, if the booking was made more than 24 hours ago, additional fees may apply. Refer to your airline's policies in your itinerary to see what changes are possible and if any costs are involved. You'll also find more details on our Customer Service portal.

Travel information

Origin airport
Watertown Regional
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Delta, United
Roundtrip price
$233
Distance
551 mi

Book with confidence

Watertown to St. Louis Flights

The cheapest times to fly from Watertown to St. Louis

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 Watertown to St. Louis are during the month of January. You can find some of the cheapest flights from Watertown to St. Louis with Expedia's search tool and vast selection of airlines.

 

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

Sunday is one of the best days to book for cheap flights from Watertown to St. Louis: 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 Watertown to St. Louis

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 Watertown to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from $233 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 Watertown to St. Louis 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 Watertown to St. Louis 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.

 

Watertown to St. Louis Flights

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*Available to One Key members.