How long is the flight from St. Louis to Washington, D.C. Dulles Intl Airport?

A quick flight from St. Louis to Washington, D.C. Dulles Intl Airport can take about 4h 11m. Delta provides one of the quickest options available for as low as $237. There are 694 mi between St. Louis and Washington, D.C. Dulles Intl Airport. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.

What are the cheapest airlines flying from St. Louis to Washington, D.C. Dulles Intl Airport round-trip?

Currently priced at $90, Frontier will fly you from St. Louis to Washington, D.C. Dulles Intl Airport and back. In addition to Frontier, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from Delta and American Airlines - these airlines can fly you to your destination from $98 and $257, respectively. Frontier is 76% cheaper than the average price of flights available within the next 90 days to this destination.

What are the cheapest airlines to fly from St. Louis to Washington, D.C. Dulles Intl Airport one-way?

To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $72. Delta flights start at $128 while deals on United Airlines start at $131 one-way.

Weekly flight availability from St. Louis to Washington, D.C. Dulles Intl Airport

The most flights from STL to IAD are scheduled on a Monday (7 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (4 on average).

In terms of precipitation, rainfall in Washington, D.C. Dulles Intl Airport ranges from 2.6 - 4.0 inches per month. May is typically the wettest month, when rainfall can reach 4.0 in. February is typically the driest time to visit Washington, D.C. Dulles Intl Airport when rainfall is around 2.6 in.

If weather is an important factor for your trip to Washington, D.C. Dulles Intl Airport, 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 35.6 F).

What are the cheapest flights from St. Louis to Washington, D.C. Dulles Intl Airport?

On average you can expect to pay $1,956 for a flight from St. Louis to Washington, D.C. Dulles Intl Airport. The cheapest flight overall is $167 while the most popular route, (Lambert-St Louis - Washington, D.C. Dulles Intl) is currently priced at $192.

What are the most reliable airlines from St. Louis to Washington, D.C. Dulles Intl Airport?

No one likes to see their flight delayed. When booking a flight from St. Louis to Washington, D.C. Dulles Intl Airport consider choosing Mesa Airlines (100%), Avianca (89%) or Copa Airlines (89%) as they are the most reliable in getting you off to your destination on time.

What are the most popular airlines that fly from St. Louis to Washington, D.C. Dulles Intl Airport?

United Airlines, Delta and Frontier are the most popular airlines when flying from St. Louis to Washington, D.C. Dulles Intl Airport.

Most accurate provider : When it comes to deals on St. Louis-Washington, D.C. Dulles Intl Airport flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Washington, D.C. Dulles Intl Airport flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Washington, D.C. Dulles Intl Airport flight searches over the past month and is updated monthly.

Most trusted provider : When it comes to deals on St. Louis-Washington, D.C. Dulles Intl Airport flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Washington, D.C. Dulles Intl Airport flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

What airport do you fly from for flights from St. Louis to Washington, D.C. Dulles Intl?

Most people fly from Lambert-St Louis (STL) if they book a flight from St. Louis to Washington, D.C. Dulles Intl. On average, Lambert-St Louis has 6 outbound flights to Washington, D.C. Dulles Intl per day from 4 airlines. Lambert-St Louis is conveniently located just 12.7 mi from St. Louis’s city center.

Can I find deals for flights from St. Louis to Dulles Intl that include hotel bookings?

Yes. In addition to deals on St. Louis to Dulles Intl flights, Cheapflights offers vacation packages that include both flights and hotel.

How can I find direct flights from St. Louis to Dulles Intl?

After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Dulles Intl.

Can I find deals for business class flights from St. Louis to Dulles Intl?

Yes. Cheapflights offers flight deals from St. Louis to Dulles Intl by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

$69+ Cheap Flights from St. Louis to Washington, D.C. Dulles Intl Airport

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Cheap flight deals from St. Louis to Dulles Intl

Cheapest

Best

Last-minute

One-way

Cheapest flights from St. Louis to Dulles Intl
Explore the most affordable flight options available from St. Louis to Dulles Intl. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 21, 2026.

Thu 9/106:00 am -

1 stop4h 30m

Mon 9/147:17 pm -

1 stop5h 25m

Deal found 8/19

$237

Tue 9/86:45 pm -

2 stops21h 33m

Mon 9/147:50 am -

1 stop6h 20m

Deal found 8/19

$239

Sun 10/45:19 pm -

1 stop15h 58m

Sat 10/1011:12 am -

1 stop13h 01m

Deal found 8/17

$240

Thu 9/106:39 pm -

1 stop14h 38m

Sun 9/136:00 am -

1 stop30h 17m

Deal found 8/18

$241

Sat 11/1410:35 am -

1 stop6h 01m

Thu 11/199:16 pm -

1 stop11h 35m

Deal found 8/17

$243

Fri 10/96:35 pm -

1 stop21h 43m

Sat 10/177:50 am -

2 stops16h 23m

Deal found 8/18

$244

Fri 9/182:29 pm -

1 stop25h 49m

Sat 9/266:00 am -

2 stops14h 17m

Deal found 8/19

$245

Mon 10/261:00 pm -

Nonstop2h 09m

Thu 10/296:11 am -

1 stop5h 21m

Deal found 8/17

$246

Thu 9/246:39 pm -

1 stop14h 38m

Sun 9/2711:12 am -

1 stop6h 22m

Deal found 8/17

$248

Wed 9/92:29 pm -

1 stop8h 41m

Tue 9/154:36 pm -

2 stops19h 56m

Deal found 8/19

$249

Thu 11/121:00 pm -

Nonstop2h 09m

Wed 11/188:40 am -

Nonstop2h 32m

Deal found 8/20

$251

Tue 9/1512:17 pm -

2 stops28h 01m

Fri 9/187:50 am -

1 stop6h 20m

Deal found 8/20

$252

Best flights from St. Louis to Dulles Intl
Discover carefully curated flight deals from St. Louis to Dulles Intl that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 21, 2026.

Tue 10/136:05 pm -

1 stop4h 11m

Mon 10/197:45 pm -

1 stop5h 09m

Deal found 8/19

$237

Mon 10/267:30 am -

1 stop5h 05m

Thu 10/298:40 am -

Nonstop2h 32m

Deal found 8/19

$240

Fri 9/256:54 pm -

1 stop4h 47m

Mon 9/287:17 pm -

1 stop5h 25m

Deal found 8/19

$256

Sat 11/148:00 am -

Nonstop2h 10m

Thu 11/198:40 am -

Nonstop2h 32m

Deal found 8/18

$271

Sat 11/1410:50 am -

1 stop4h 07m

Thu 11/196:00 am -

1 stop6h 15m

Deal found 8/20

$291

Mon 9/216:00 am -

1 stop4h 49m

Wed 9/235:45 pm -

Nonstop2h 29m

Deal found 8/17

$333

Thu 10/227:20 pm -

1 stop4h 22m

Sun 10/256:05 am -

1 stop4h 39m

Deal found 8/17

$324

Fri 9/255:36 pm -

1 stop4h 16m

Tue 9/298:20 am -

Nonstop2h 21m

Deal found 8/17

$349

Thu 9/31:00 pm -

Nonstop2h 06m

Mon 9/78:20 am -

1 stop4h 42m

Deal found 8/16

$368

Fri 9/118:40 am -

Nonstop2h 14m

Sun 9/205:45 pm -

Nonstop2h 26m

Deal found 8/17

$370

Last-minute flights from St. Louis to Dulles Intl
Discover last-minute flight deals from St. Louis to Dulles Intl. Data last updated August 21, 2026 and is based on user searches.

Tue 9/86:45 pm -

2 stops21h 33m

Mon 9/147:50 am -

1 stop6h 20m

Deal found 8/19

$239

Tue 9/86:45 pm -

2 stops21h 33m

Wed 9/167:50 am -

1 stop6h 20m

Deal found 8/19

$255

Wed 9/92:29 pm -

1 stop8h 41m

Tue 9/154:36 pm -

2 stops19h 56m

Deal found 8/19

$249

Thu 9/106:00 am -

1 stop4h 30m

Thu 9/176:10 am -

1 stop4h 19m

Deal found 8/19

$237

Thu 9/106:39 pm -

1 stop14h 38m

Sun 9/136:00 am -

1 stop30h 17m

Deal found 8/18

$241

Fri 9/115:46 pm -

1 stop5h 55m

Tue 9/1510:15 am -

1 stop6h 39m

Deal found 8/19

$256

Tue 9/1512:17 pm -

2 stops28h 01m

Fri 9/187:50 am -

1 stop6h 20m

Deal found 8/20

$252

Fri 9/182:29 pm -

1 stop25h 49m

Sat 9/266:00 am -

2 stops14h 17m

Deal found 8/19

$245

Wed 9/236:00 pm -

Nonstop2h 06m

Thu 9/246:10 am -

1 stop7h 03m

Deal found 8/19

$261

Thu 9/246:39 pm -

1 stop14h 38m

Sun 9/2711:12 am -

1 stop6h 22m

Deal found 8/17

$248

One-way flights from St. Louis to Dulles Intl
Search for one-way flight options from St. Louis to Dulles Intl. Find affordable one-way fares based on user searches. Data last updated August 21, 2026.

Thu 11/510:35 am -

1 stop6h 01m

Deal found 8/19

$69

Fri 10/22:29 pm -

1 stop25h 49m

Deal found 8/21

$77

Wed 9/232:29 pm -

1 stop8h 41m

Deal found 8/17

$80

Fri 10/166:35 pm -

1 stop4h 46m

Deal found 8/18

$87

Fri 10/96:35 pm -

1 stop4h 46m

Deal found 8/18

$88

Tue 9/1512:17 pm -

1 stop17h 03m

Deal found 8/18

$92

Thu 9/106:39 pm -

1 stop14h 38m

Deal found 8/17

$93

Thu 9/246:39 pm -

1 stop14h 38m

Deal found 8/17

$95

Fri 9/182:29 pm -

1 stop8h 41m

Deal found 8/21

$97

Mon 10/126:35 pm -

1 stop4h 46m

Deal found 8/18

$99

Find flight deals from St. Louis to Dulles Intl

Most accurate provider	FlightHub 3 stars
Most trusted provider	FlightHub 3 stars
Round-trip from	$237 (Delta)
One-way from	$69 (Kiwi.com)
Popular in	June
Cheapest in	February
Average price	$460
Good round-trip deal	$695 or less
Good one-way deal	$261 or less

Provider with most accurate pricing for Lambert-St Louis-Washington, D.C. Dulles Intl flight deals.

Search Deals

Provider most trusted by Cheapflights users for Lambert-St Louis-Washington, D.C. Dulles Intl flights.

Search Deals

From Lambert-St Louis to Washington, D.C. Dulles Intl

Search Deals

One-way flight from Lambert-St Louis to Washington, D.C. Dulles Intl

Search Deals

Highest demand for flights based on searches. 8% potential increase in price ($33 potential increase over avg. RT price).

Search Deals

Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).

Search Deals

Average for round-trip flights in August 2026

Search Deals

Price to beat on a round-trip flight from Lambert-St Louis to Washington, D.C. Dulles Intl.

Search Deals

Price to beat on a one-way flight from Lambert-St Louis to Washington, D.C. Dulles Intl.

Search Deals

Cheapflights Fare Finder

Use the filters below to find and compare flights from St. Louis to Washington, D.C. Dulles Intl Airport that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Tue 10/13

6:05 pm-11:16 pm

1 stop4h 11m

Washington, D.C. Dulles Intl

Mon 10/19

7:45 pm-11:54 pm

1 stop5h 09m

$237

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Mon 10/26

7:30 am-1:35 pm

1 stop5h 05m

Washington, D.C. Dulles Intl

Thu 10/29

8:40 am-10:12 am

Nonstop2h 32m

$240

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Fri 9/25

6:54 pm-12:41 am

1 stop4h 47m

Washington, D.C. Dulles Intl

Mon 9/28

7:17 pm-11:42 pm

1 stop5h 25m

$256

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Sat 11/14

8:00 am-11:10 am

Nonstop2h 10m

Washington, D.C. Dulles Intl

Thu 11/19

8:40 am-10:12 am

Nonstop2h 32m

$271

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Sat 11/14

10:50 am-3:57 pm

1 stop4h 07m

Washington, D.C. Dulles Intl

Thu 11/19

6:00 am-11:15 am

1 stop6h 15m

$291

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Thu 10/22

7:20 pm-12:42 am

1 stop4h 22m

Washington, D.C. Dulles Intl

Sun 10/25

6:05 am-9:44 am

1 stop4h 39m

$324

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Mon 9/21

6:00 am-11:49 am

1 stop4h 49m

Washington, D.C. Dulles Intl

Wed 9/23

5:45 pm-7:14 pm

Nonstop2h 29m

$333

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Fri 9/25

5:36 pm-10:52 pm

1 stop4h 16m

Washington, D.C. Dulles Intl

Tue 9/29

8:20 am-9:41 am

Nonstop2h 21m

$349

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Thu 9/3

1:00 pm-4:06 pm

Nonstop2h 06m

Washington, D.C. Dulles Intl

Mon 9/7

8:20 am-12:02 pm

1 stop4h 42m

$368

Quickest round-trip

St. LouisWashington, D.C.

STL Lambert-St Louis - IAD Washington, D.C. Dulles Intl

STLIAD

Lambert-St Louis

Fri 9/11

8:40 am-11:54 am

Nonstop2h 14m

Washington, D.C. Dulles Intl

Sun 9/20

5:45 pm-7:11 pm

Nonstop2h 26m

$370

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/19

Showing 1-10 of 20 resultsSorted by cheapest first

Compare providers for flights from St. Louis to Dulles Intl

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from St. Louis to Dulles Intl in August.

Provider	Price Accuracy	Trust Score*
Expedia	Price Accuracy1 star	Trust Score*3 stars
FlightHub	Price Accuracy3 stars	Trust Score*3 stars

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

Most accurate provider: When it comes to deals on St. Louis-Washington, D.C. Dulles Intl Airport flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on St. Louis-Washington, D.C. Dulles Intl Airport flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from St. Louis-Washington, D.C. Dulles Intl Airport flight searches over the past month and is updated monthly.
Most trusted provider: When it comes to deals on St. Louis-Washington, D.C. Dulles Intl Airport flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for St. Louis-Washington, D.C. Dulles Intl Airport flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from St. Louis to Dulles Intl

Have a flexible travel schedule? Discover the best time to fly to Dulles Intl from St. Louis with our price prediction graph.

STL-IAD

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 St. Louis to Washington, D.C. Dulles Intl Airport

Prices

Airlines

What is the cheapest month to book a flight from St. Louis to Washington, D.C. Dulles Intl Airport?

Currently, February is the cheapest month in which you can book a flight from St. Louis to Washington, D.C. Dulles Intl Airport (average of $170). Flying from St. Louis to Washington, D.C. Dulles Intl Airport in June is currently the most expensive (average of $477). 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 IAD?

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from St. Louis to Washington, D.C. Dulles Intl Airport as you normally would.

How much does it cost to fly round-trip from St. Louis to Washington, D.C. Dulles Intl Airport?

Airfare is below average for this route at the moment.

St. Louis to Washington, D.C. Dulles Intl Airport flights typically cost between $290 and $582 in September.
The cheapest round-trip price found within the last 5 days was $237 on Delta (Sep 10-Sep 17).

The best insider tips for St. Louis to Washington, D.C. Dulles Intl Airport flights

Cheapflights partnered with top experts to bring you the best recommendations for your St. Louis to Washington, D.C. Dulles Intl Airport trip

Our travel experts

Taryn White

Expert on STL

Taryn White is a freelance travel writer, digital creator, and travel advisor who has visited nearly 100 countries and all 50 states. She’s familiar with many airports and enjoys beach hopping, boutique hotels, spa experiences, and exploring local culture. Her work has appeared in Travel + Leisure, Condé Nast Traveler, National Geographic, Smithsonian Magazine, AFAR, and more.

Ramsey Qubein

Expert on IAD

An avid traveler and aviation expert who has visited 173 countries, all 50 states and seven continents, Ramsey Qubein flies nearly 400,000 miles a year. As a North Carolina-based freelance journalist for publications including Conde Nast Traveler, Forbes, USA Today and Bloomberg among others, he explores the latest trends in aviation, hospitality, cruises and business.

Peruse reviews from past customers who have flown with Delta,United Airlines, andAmerican Airlines from St. Louis to Washington, D.C. Dulles Intl Airport to help guide your decision. You can also see how each airline stacks up in terms of entertainment options, comfort, food, crew/service, and boarding process.

Delta

7.8

Good

8,510 reviews

Reviews

1 / 20

10.0

Excellent

Salvador,Aug 2026

PHL - DTW

No food and entertainment. Also de aircraft is old and noisy.

Delta

7.8

Good

8,510 reviews

Delta

7.8

Good

8,510 reviews

Reviews

1 / 20

10.0

Excellent

Salvador,Aug 2026

PHL - DTW

No food and entertainment. Also de aircraft is old and noisy.

United Airlines

7.4

Good

10,104 reviews

Delta

7.8

Good

8,510 reviews

Reviews

1 / 20

10.0

Excellent

Salvador,Aug 2026

PHL - DTW

No food and entertainment. Also de aircraft is old and noisy.

American Airlines

7.1

Good

11,979 reviews

Delta

7.8

Good

8,510 reviews

Reviews

1 / 20

10.0

Excellent

Salvador,Aug 2026

PHL - DTW

No food and entertainment. Also de aircraft is old and noisy.

Frontier

5.6

Fair

2,661 reviews

Delta

7.8

Good

8,510 reviews

Reviews

1 / 20

10.0

Excellent

Salvador,Aug 2026

PHL - DTW

No food and entertainment. Also de aircraft is old and noisy.

Related info for your journey

What airport do you fly from for flights from St. Louis to Washington, D.C. Dulles Intl?
Most people fly from Lambert-St Louis (STL) if they book a flight from St. Louis to Washington, D.C. Dulles Intl. On average, Lambert-St Louis has 6 outbound flights to Washington, D.C. Dulles Intl per day from 4 airlines. Lambert-St Louis is conveniently located just 12.7 mi from St. Louis’s city center.
How long is the flight from St. Louis to Washington, D.C. Dulles Intl Airport?
A quick flight from St. Louis to Washington, D.C. Dulles Intl Airport can take about 4h 11m. Delta provides one of the quickest options available for as low as $237. There are 694 mi between St. Louis and Washington, D.C. Dulles Intl Airport. When browsing for deals, the options you’ll see will be for both nonstop flights and flights with stops.
What are the cheapest airlines flying from St. Louis to Washington, D.C. Dulles Intl Airport round-trip?
Currently priced at $90, Frontier will fly you from St. Louis to Washington, D.C. Dulles Intl Airport and back. In addition to Frontier, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from Delta and American Airlines - these airlines can fly you to your destination from $98 and $257, respectively. Frontier is 76% cheaper than the average price of flights available within the next 90 days to this destination.
What are the cheapest airlines to fly from St. Louis to Washington, D.C. Dulles Intl Airport one-way?
To fly one-way, consider booking your trip with Frontier, which is currently one of the cheapest options available, starting at $72. Delta flights start at $128 while deals on United Airlines start at $131 one-way.
What are the most reliable airlines from St. Louis to Washington, D.C. Dulles Intl Airport?
No one likes to see their flight delayed. When booking a flight from St. Louis to Washington, D.C. Dulles Intl Airport consider choosing Mesa Airlines (100%), Avianca (89%) or Copa Airlines (89%) as they are the most reliable in getting you off to your destination on time.
What are the cheapest flights from St. Louis to Washington, D.C. Dulles Intl Airport?
On average you can expect to pay $1,956 for a flight from St. Louis to Washington, D.C. Dulles Intl Airport. The cheapest flight overall is $167 while the most popular route, (Lambert-St Louis - Washington, D.C. Dulles Intl) is currently priced at $192.
Can I find deals for flights from St. Louis to Dulles Intl that include hotel bookings?
Yes. In addition to deals on St. Louis to Dulles Intl flights, Cheapflights offers vacation packages that include both flights and hotel.
How can I find direct flights from St. Louis to Dulles Intl?
After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from St. Louis to Dulles Intl.
Can I find deals for business class flights from St. Louis to Dulles Intl?
Yes. Cheapflights offers flight deals from St. Louis to Dulles Intl 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 Washington, D.C. Dulles Intl Airport?
Currently, February is the cheapest month in which you can book a flight from St. Louis to Washington, D.C. Dulles Intl Airport (average of $170). Flying from St. Louis to Washington, D.C. Dulles Intl Airport in June is currently the most expensive (average of $477). 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

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Alternative routes

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Top 4 airlines flying from St. Louis to Dulles Intl

Airline	Cheapest	Average	Flexibility	On-time
Frontier	Cheapest$90	Average$184	FlexibilityNo cancel fee	On-time62%
Delta	Cheapest$98	Average$334	FlexibilityNo cancel fee	On-timeN/A
American Airlines	Cheapest$257	Average$328	FlexibilityNo cancel fee	On-time71%
United Airlines	Cheapest$271	Average$465	FlexibilityNo cancel fee	On-time69%

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$69+ Cheap flights from St. Louis (STL) to Dulles Intl (IAD)

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 11/5. Fares are subject to change and may not be available on all flights or dates of travel.

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Cheap flight deals from St. Louis to Dulles Intl

Cheapest flights from St. Louis to Dulles IntlExplore the most affordable flight options available from St. Louis to Dulles Intl. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 21, 2026.

Explore the most affordable flight options available from St. Louis to Dulles Intl. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 21, 2026.

Best flights from St. Louis to Dulles IntlDiscover carefully curated flight deals from St. Louis to Dulles Intl that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 21, 2026.

Discover carefully curated flight deals from St. Louis to Dulles Intl that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 21, 2026.

Last-minute flights from St. Louis to Dulles IntlDiscover last-minute flight deals from St. Louis to Dulles Intl. Data last updated August 21, 2026 and is based on user searches.

Discover last-minute flight deals from St. Louis to Dulles Intl. Data last updated August 21, 2026 and is based on user searches.

One-way flights from St. Louis to Dulles IntlSearch for one-way flight options from St. Louis to Dulles Intl. Find affordable one-way fares based on user searches. Data last updated August 21, 2026.

Search for one-way flight options from St. Louis to Dulles Intl. Find affordable one-way fares based on user searches. Data last updated August 21, 2026.

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Use the filters below to find and compare flights from St. Louis to Washington, D.C. Dulles Intl Airport that are best for you.

Compare providers for flights from St. Louis to Dulles Intl

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.

Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from St. Louis to Dulles Intl in August.

Best time to book a flight from St. Louis to Dulles Intl

Have a flexible travel schedule? Discover the best time to fly to Dulles Intl from St. Louis with our price prediction graph.

Cheapflights Insights

What is the cheapest month to book a flight from St. Louis to Washington, D.C. Dulles Intl Airport?

What is the cheapest time of day to fly from STL to IAD?

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from St. Louis to Washington, D.C. Dulles Intl Airport as you normally would.

How much does it cost to fly round-trip from St. Louis to Washington, D.C. Dulles Intl Airport?

Airfare is below average for this route at the moment.

St. Louis to Washington, D.C. Dulles Intl Airport flights typically cost between $290 and $582 in September.The cheapest round-trip price found within the last 5 days was $237 on Delta (Sep 10-Sep 17).

Weekly flight availability from St. Louis to Washington, D.C. Dulles Intl Airport

The most flights from STL to IAD are scheduled on a Monday (7 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (4 on average).

The best insider tips for St. Louis to Washington, D.C. Dulles Intl Airport flights

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Cheapflights partnered with top experts to bring you the best recommendations for your St. Louis to Washington, D.C. Dulles Intl Airport trip

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Alternative routes for St. Louis to Dulles Intl

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Other flights to Dulles Intl

Explore flights to Dulles Intl departing from other origins. Flights are based on user searches made on Cheapflights and were last updated on August 21, 2026.

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St. Louis and Dulles Intl flights

Browse other St. Louis and Dulles Intl flight options. Last updated on August 21, 2026.

Other flights from St. Louis

Browse through other flights departing from St. Louis. Flights are based on user searches made on Cheapflights and were last updated on August 21, 2026.

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Top 4 airlines flying from St. Louis to Dulles Intl

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Cheapest flights from St. Louis to Dulles Intl
Explore the most affordable flight options available from St. Louis to Dulles Intl. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 21, 2026.

Best flights from St. Louis to Dulles Intl
Discover carefully curated flight deals from St. Louis to Dulles Intl that have cost, travel time, and layovers in mind to ensure you get the best travel experience. Data last updated August 21, 2026.

Last-minute flights from St. Louis to Dulles Intl
Discover last-minute flight deals from St. Louis to Dulles Intl. Data last updated August 21, 2026 and is based on user searches.

One-way flights from St. Louis to Dulles Intl
Search for one-way flight options from St. Louis to Dulles Intl. Find affordable one-way fares based on user searches. Data last updated August 21, 2026.

St. Louis to Washington, D.C. Dulles Intl Airport flights typically cost between $290 and $582 in September.
The cheapest round-trip price found within the last 5 days was $237 on Delta (Sep 10-Sep 17).