$85 Cheap Flights from Washington (IAD) to St. Louis (STL)

View $85 flight on Thu, Nov 13, 2025Opens in a new window

Popular airlines from Washington Dulles Intl. Airport (IAD) to St. Louis Lambert Intl. Airport (STL)

Cheap Flights from Washington to St. Louis (IAD-STL)

Prices were available within the past 7 days and start at $85 for one-way flights and $118 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Thu, Nov 13 - Thu, Dec 4
IAD
Washington
STL
St. Louis
$118 Roundtrip, found 2 days ago
$118
Roundtrip
found 2 days ago
Select Frontier Airlines flight, departing Thu, Nov 13 from Washington to St. Louis, returning Thu, Dec 4, priced at $118 found 2 days ago
Frontier Airlines
Thu, Oct 23 - Thu, Nov 13
IAD
Washington
STL
St. Louis
$151 Roundtrip, found 1 day ago
$151
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Thu, Oct 23 from Washington to St. Louis, returning Thu, Nov 13, priced at $151 found 1 day ago
Frontier Airlines
Fri, Nov 7 - Thu, Nov 13
IAD
Washington
STL
St. Louis
$167 Roundtrip, found 19 hours ago
$167
Roundtrip
found 19 hours ago
Select Frontier Airlines flight, departing Fri, Nov 7 from Washington to St. Louis, returning Thu, Nov 13, priced at $167 found 19 hours ago
Delta
Tue, Nov 11 - Thu, Nov 13
IAD
Washington
STL
St. Louis
$169 Roundtrip, found 1 day ago
$169
Roundtrip
found 1 day ago
Select Delta flight, departing Tue, Nov 11 from Washington to St. Louis, returning Thu, Nov 13, priced at $169 found 1 day ago
Frontier Airlines
Thu, Oct 23 - Fri, Oct 31
IAD
Washington
STL
St. Louis
$172 Roundtrip, found 1 day ago
$172
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Thu, Oct 23 from Washington to St. Louis, returning Fri, Oct 31, priced at $172 found 1 day ago
Frontier Airlines
Thu, Oct 30 - Fri, Oct 31
IAD
Washington
STL
St. Louis
$177 Roundtrip, found 3 hours ago
$177
Roundtrip
found 3 hours ago
Select Frontier Airlines flight, departing Thu, Oct 30 from Washington to St. Louis, returning Fri, Oct 31, priced at $177 found 3 hours ago
Frontier Airlines
Thu, Oct 23 - Thu, Oct 30
IAD
Washington
STL
St. Louis
$184 Roundtrip, found 14 hours ago
$184
Roundtrip
found 14 hours ago
Select Frontier Airlines flight, departing Thu, Oct 23 from Washington to St. Louis, returning Thu, Oct 30, priced at $184 found 14 hours ago
United
Fri, Nov 7 - Fri, Nov 14
IAD
Washington
STL
St. Louis
$192 Roundtrip, found 8 hours ago
$192
Roundtrip
found 8 hours ago
Select United flight, departing Fri, Nov 7 from Washington to St. Louis, returning Fri, Nov 14, priced at $192 found 8 hours ago
Southwest Airlines
Wed, Nov 12 - Sat, Nov 15
IAD
Washington
STL
St. Louis
$209 Roundtrip, found 2 hours ago
$209
Roundtrip
found 2 hours ago
Select Southwest Airlines flight, departing Wed, Nov 12 from Washington to St. Louis, returning Sat, Nov 15, priced at $209 found 2 hours ago
American Airlines
Wed, Nov 5 - Tue, Nov 11
IAD
Washington
STL
St. Louis
$277 Roundtrip, found 5 days ago
$277
Roundtrip
found 5 days ago
Select American Airlines flight, departing Wed, Nov 5 from Washington to St. Louis, returning Tue, Nov 11, priced at $277 found 5 days ago

Find the cheapest month to fly from Washington (IAD) to St. Louis (STL)

September is typically the cheapest month to fly

From $154 - $435 per traveler.

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 $317
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $317

Frequently asked questions

How much does a flight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL) cost?
Grab a cheap one-way flight from $85 or cheap return flight from $118 from Washington Dulles Intl. Airport (IAD) 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 deals on this route.
What is the cheapest month to fly from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
Planning your trip for November is a good way to save, as it's the cheapest month for flights between IAD and STL. You'll typically find the lowest fares during off-peak months.
Which airlines fly direct from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
Jump on a nonstop flight with United Airlines and head straight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL).
What is the cheapest airline that flies from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
Expedia's filter tool lets you easily compare airlines, flight times and fares all in one place. Select your preferences, then sort by "Price (lowest to highest)" to find the carrier with the cheapest IAD to STL flight.
How many flights per day from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
When departing from Washington Dulles Intl. Airport (IAD), you can pick from an average of 2 daily nonstop flights to Lambert-St. Louis Intl. Airport (STL).
What are the most popular departure times for flights from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
The 8 AM departures from IAD to STL are typically the busiest. They can also be more expensive. If you're hoping to save money, pick a less crowded time to fly.
What day of the week has the most flights from IAD to STL?
Depart on a Friday if you're searching for the biggest selection of flights from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL).
What is the earliest flight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
The earliest flight out of Washington Dulles Intl. Airport (IAD) is at around 8:50AM UTC-5. Catch this flight and you'll arrive at Lambert-St. Louis Intl. Airport (STL) at approximately 10:24AM UTC-6. The total travel time is 2h 34m.
How long does it take to fly from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
Flights from IAD to STL have an average travel time of 2 hours and 34 minutes. The distance between the two airports is 700 mi.
What is the best time to fly from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
Select a flight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL) that takes off before 3 PM to reduce the risk of delays and cancellations. Departures after this hour are on average 22% more likely to be canceled.**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.
What airports do you fly into for St. Louis from Washington Dulles Intl. Airport (IAD)?
Compare your flight options from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL). This is the only airport in St. Louis you can arrive at if you're taking a direct flight.
Is it cheaper to buy a plane ticket from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL) last-minute?
Booking your ticket from IAD to STL shortly before your trip is typically more expensive. But if you're flexible with your travel dates and times, you could bag a cheap last-minute fare.
Is it cheaper to book an IAD to STL flight and hotel package?
Compared with arranging hotels and flights separately, booking an IAD to STL flight and hotel package with Expedia could lead to significant savings. What's more, having it all in one place will take the hassle out of travel planning. Just secure your flights and select from our wide range of hotels, then customize your trip with extras like tours, car rentals and activities.
Can I cancel or change the date of my flight from Washington Dulles Intl. Airport (IAD) to Lambert-St. Louis Intl. Airport (STL)?
In most cases, you can cancel or reschedule your IAD to STL flight. However, additional charges may apply, especially if you booked over 24 hours ago. Check your itinerary for the airline's fees and rules on flight changes, or if you'd like more information, visit our Customer Service portal.

Travel information

Origin airport
Washington Dulles Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
American Airlines, Delta, Frontier Airlines, Southwest Airlines, United
Roundtrip price
$112
Distance
694 mi
Average flight time
1 hour 23 mins

Book with confidence

Washington to St. Louis Flights

The cheapest times to fly from Washington 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 Washington to St. Louis are during the month of November. You can find some of the cheapest flights from Washington to St. Louis with Expedia's search tool and vast selection of airlines.

 

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

Sunday is one of the best days to book for cheap flights from Washington 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 Washington 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 Washington to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from $85 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 Washington 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 Washington 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.

 

Washington to St. Louis Flights

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*Available to One Key members.