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

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 2/6. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — STL
Jan 20 — Jan 271
Tue 1/20
Tue 1/27
1 adult, Economy
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Find cheap flights from Dulles Intl to St. Louis 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

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3. Compare prices and book

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Cheapflights Tip: The best prices from Washington, D.C. Dulles Intl to Lambert-St Louis are usually found in August or July, booked 75 days in advance, depart on a Saturday or Wednesday and return on a Friday

Cheap flight deals from Dulles Intl to St. Louis

Cheapest flights from Dulles Intl to St. Louis
Explore the most affordable flight options available from Dulles Intl to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on December 21, 2025.

This Frontier deal was found by Cheapflights users on 12/19. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/289:58 pmIAD - STL
1 stop12h 47mFrontier
Thu 1/110:42 amSTL - IAD
1 stop6h 34mFrontier
Deal found 12/19$308
This Expedia deal was found by Cheapflights users on 12/19. 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 Expedia is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 12/309:58 pmIAD - STL
1 stop25h 35mFrontier
Sun 1/410:57 amSTL - IAD
1 stop5h 01mFrontier
Deal found 12/19$377
This Delta deal was found by Cheapflights users on 12/19. 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.
Tue 12/304:55 pmIAD - STL
1 stop25h 04mDelta
Thu 1/16:29 amSTL - IAD
1 stop4h 23mDelta
Deal found 12/19$383
This Frontier deal was found by Cheapflights users on 12/19. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 12/289:58 pmIAD - STL
1 stop12h 47mFrontier
Sun 1/410:57 amSTL - IAD
1 stop5h 01mFrontier
Deal found 12/19$402
This Kiwi.com deal was found by Cheapflights users on 12/20. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 12/292:09 pmIAD - STL
2 stops20h 31mFrontier
Sun 1/410:57 amSTL - IAD
1 stop23h 41mFrontier
Deal found 12/20$425
This Kiwi.com deal was found by Cheapflights users on 12/19. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/277:11 pmIAD - STL
1 stop15h 29mFrontier
Sun 1/410:57 amSTL - IAD
1 stop23h 41mFrontier
Deal found 12/19$441
This Kiwi.com deal was found by Cheapflights users on 12/19. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 12/257:11 pmIAD - STL
2 stops14h 01mFrontier
Sun 1/410:57 amSTL - IAD
1 stop23h 41mFrontier
Deal found 12/19$465
This Kiwi.com deal was found by Cheapflights users on 12/19. 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 Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 12/242:35 pmIAD - STL
2 stops21h 21mMultiple Airlines
Sun 1/410:57 amSTL - IAD
1 stop23h 41mMultiple Airlines
Deal found 12/19$471
This Delta deal was found by Cheapflights users on 12/19. 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.
Fri 12/266:00 amIAD - STL
1 stop7h 21mDelta
Wed 12/315:13 pmSTL - IAD
1 stop4h 39mDelta
Deal found 12/19$479

Find flight deals from Dulles Intl to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Dulles Intl (IAD) to St. Louis (STL). 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 December 21, 2025.

Most accurate provider

eDreams
3 stars

Most trusted provider

eDreams
3 stars

Round-trip from

$258
(Kiwi.com)

One-way from

$69
(Trip.com)

Popular in

November

Cheapest in

August

Average price

$403

Good round-trip deal

$349 or less

Good one-way deal

$234 or less
Provider with most accurate pricing for Washington, D.C. Dulles Intl-Lambert-St Louis flight deals.
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Provider most trusted by Cheapflights users for Washington, D.C. Dulles Intl-Lambert-St Louis flights.
Search Deals
From Washington, D.C. Dulles Intl to Lambert-St Louis
Search Deals
One-way flight from Washington, D.C. Dulles Intl to Lambert-St Louis
Search Deals
Highest demand for flights based on searches. 12% potential increase in price ($54 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 3% potential price decrease ($14 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in December 2025
Search Deals
Price to beat on a round-trip flight from Washington, D.C. Dulles Intl to Lambert-St Louis.
Search Deals
Price to beat on a one-way flight from Washington, D.C. Dulles Intl to Lambert-St Louis.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Dulles Intl to St. Louis 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 December 21, 2025.
Use the filters below to find and compare flights from Washington, D.C. Dulles Intl Airport to St. Louis that are best for you.

Fly from

Dulles Intl

Fly to

St. Louis

Route

Depart

Return

Price

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Mon 2/2

1:31 pm-11:33 pm

1 stop11h 02m

Lambert-St Louis

Thu 2/5

5:42 pm-8:40 am

1 stop13h 58m

$264

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 1/22

8:40 am-10:13 am

Nonstop2h 33m

Lambert-St Louis

Sat 1/24

12:44 pm-3:55 pm

Nonstop2h 11m

$265

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sat 1/17

6:00 am-10:41 am

1 stop5h 41m

Lambert-St Louis

Mon 1/19

12:44 pm-3:55 pm

Nonstop2h 11m

$271

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 1/15

5:38 pm-11:59 pm

1 stop7h 21m

Lambert-St Louis

Sun 1/18

8:30 am-11:40 am

Nonstop2h 10m

$282

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Thu 2/19

10:10 am-11:59 pm

1 stop14h 49m

Lambert-St Louis

Sun 2/22

3:49 pm-4:08 pm

2 stops23h 19m

$289

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sun 2/1

8:40 am-10:13 am

Nonstop2h 33m

Lambert-St Louis

Sat 2/7

8:30 am-11:40 am

Nonstop2h 10m

$298

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sun 1/25

8:40 am-10:13 am

Nonstop2h 33m

Lambert-St Louis

Wed 1/28

8:30 am-11:40 am

Nonstop2h 10m

$298

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sat 4/25

9:00 am-10:31 am

Nonstop2h 31m

Lambert-St Louis

Wed 4/29

8:21 am-4:03 pm

1 stop6h 42m

$305

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sat 1/17

5:38 pm-11:59 pm

1 stop7h 21m

Lambert-St Louis

Sun 1/18

8:30 am-11:40 am

Nonstop2h 10m

$308

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sun 1/11

8:40 am-10:13 am

Nonstop2h 33m

Lambert-St Louis

Tue 1/13

8:30 am-11:40 am

Nonstop2h 10m

$309

Flights are sorted by cheapest round-trip flights first.

Deals found on 12/21

Showing 1-10 of 20 results
1
2

Compare providers for flights from Dulles Intl to St. Louis

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 Dulles Intl to St. Louis in December.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy2 starsTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*1 star
eDreamsPrice Accuracy3 starsTrust Score*3 stars
PricelinePrice Accuracy1 starTrust 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 Washington, D.C. Dulles Intl Airport-St. Louis flights, users find the pricing of eDreams to be most consistent on Cheapflights vs. eDreams Users can find the same prices on Washington, D.C. Dulles Intl Airport-St. Louis flight deals on Cheapflights vs. eDreams >95% of the time. Price accuracy is based on data collected from Washington, D.C. Dulles Intl Airport-St. Louis flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Washington, D.C. Dulles Intl Airport-St. Louis flights, Cheapflights users trust eDreams the most. eDreams 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 Washington, D.C. Dulles Intl Airport-St. Louis 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 Dulles Intl to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Dulles Intl 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.

Cheapflights Insights

Everything you need to know about your flight from Washington, D.C. Dulles Intl Airport to St. Louis

How far ahead should I book a flight from Washington, D.C. Dulles Intl Airport to St. Louis?

Use this chart to determine the optimal time to book a round-trip flight from Dulles Intl to St. Louis. Price data was last updated on December 12, 2025.

The best time to book flights from Washington, D.C. Dulles Intl Airport to St. Louis is 69 days before your desired departure date. The cost of your flight will likely increase significantly if you book two weeks in advance of your flight.

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

Currently, October is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to St. Louis (average of $124). Flying from Washington, D.C. Dulles Intl Airport to St. Louis in November is currently the most expensive (average of $288). 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 IAD to STL?

Find hourly flight availability from Dulles Intl to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated December 21, 2025.

It’s typically best to fly out from Washington, D.C. Dulles Intl Airport to St. Louis in the evening. Doing so could potentially save you 38% on the flight price compared to flying in the afternoon, which is usually more expensive.

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

AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your Washington, D.C. Dulles Intl Airport to St. Louis trip
Airports
IAD

For quick check-in at IAD, locate your airline’s counter by walking around the first row. Counters are like an island with desks on both sides.

Read more about IADBy Ramsey Qubein
STL

Use the MetroLink light rail for a convenient, economical ride from STL to downtown St. Louis. It takes about 40 minutes and avoids traffic.

Read more about STLBy Taryn White
Our travel experts
Taryn White

Taryn White

Expert on STL

Taryn White

Taryn White

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.

Read more
Ramsey Qubein

Ramsey Qubein

Expert on IAD

Ramsey Qubein

Ramsey Qubein

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.

Read more

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. 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 St. Louis. Reviews last updated December 21, 2025.
Get a feel of what it's like to fly with Delta, United Airlines, and American Airlines from Washington, D.C. Dulles Intl Airport to St. Louis by reading reviews from past customers. Users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Delta
7.9
Good
8,021 reviews

Overall

7.9

Comfort

7.9

Boarding

8.1

Food

7.3

Crew

8.5

Entertainment

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
Delta
7.9
Good
8,021 reviews
Delta
7.9
Good
8,021 reviews

Overall

7.9

Comfort

7.9

Boarding

8.1

Food

7.3

Crew

8.5

Entertainment

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
United Airlines
7.4
Good
9,099 reviews
Delta
7.9
Good
8,021 reviews

Overall

7.9

Comfort

7.9

Boarding

8.1

Food

7.3

Crew

8.5

Entertainment

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
American Airlines
7.2
Good
11,050 reviews
Delta
7.9
Good
8,021 reviews

Overall

7.9

Comfort

7.9

Boarding

8.1

Food

7.3

Crew

8.5

Entertainment

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.
Frontier
5.8
Fair
3,082 reviews
Delta
7.9
Good
8,021 reviews

Overall

7.9

Comfort

7.9

Boarding

8.1

Food

7.3

Crew

8.5

Entertainment

7.9

Reviews

1 / 20
6.0
Good

Jim,Nov 2025

AVL - ATL

The exit row seats without a seat in front are great for leg room but don’t have a fold out entertainment console so you’re forced to use the screen several feet in front of you (there is, at least, a remote). Best to bring a tablet loaded with entertainment or a book.

Related info for your journey

Find useful and relevant information for your journey from Dulles Intl to St. Louis. 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 into for flights to St. Louis from Washington, D.C. Dulles Intl?

    If you book a flight to St. Louis from Washington, D.C. Dulles Intl, you will be flying to Lambert-St Louis, which is the city’s only airport. Lambert-St Louis (STL) is located 12.7 mi from the center of St. Louis. There are 8 flights from Washington, D.C. Dulles Intl to Lambert-St Louis per day from 4 different airlines.

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

    Airlines like Frontier and United Airlines fly from Washington, D.C. Dulles Intl Airport to St. Louis in about 2h 33m. The time it takes to get you to your destination can typically vary by up to 8h 29m. The distance from Washington, D.C. Dulles Intl Airport to St. Louis is about 694 mi. 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 Washington, D.C. Dulles Intl Airport to St. Louis round-trip?

    Cheapflights users have booked flights from Washington, D.C. Dulles Intl Airport to St. Louis round-trip from $78. Other airlines that can offer you cheap pricing are Delta, from $124, and United Airlines, from $239. These flights start at 80% lower than the current average price 3 months from now.

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

    The cheapest airlines for a one-way flight from Washington, D.C. Dulles Intl Airport to St. Louis are Frontier ($58), Delta ($99), and United Airlines ($123).

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

    Consider GoJet (72%), Avianca (72%) or Copa Airlines (72%) when booking your flight. These represent the most reliable airlines when flying from Washington, D.C. Dulles Intl Airport to St. Louis.

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

    Looking for the cheapest flight from Washington, D.C. Dulles Intl Airport to St. Louis? While on average our users pay $364, our data indicates the cheapest price to be $66. The most popular route (Washington, D.C. Dulles Intl - Lambert-St Louis), is priced around $154.

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

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

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

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

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

    Yes. Cheapflights offers flight deals from Dulles Intl to St. Louis 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 Washington, D.C. Dulles Intl Airport to St. Louis?

    Currently, October is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to St. Louis (average of $124). Flying from Washington, D.C. Dulles Intl Airport to St. Louis in November is currently the most expensive (average of $288). 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

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
Edwardsville
O'Fallon
Fairview Heights
Maryland Heights
Collinsville
Swansea
Eureka
Glencoe
St. Peters
Chesterfield
Alton
Farmington
Festus

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Alternative routes for Dulles Intl to St. Louis

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Top 4 airlines flying from Dulles Intl to St. Louis

Discover the top 4 airlines that operate flights from Dulles Intl to St. Louis. 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 December 21, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$78Average$223FlexibilityNo cancel feeOn-time62%
DeltaCheapest$149Average$300FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$243Average$464FlexibilityNo cancel feeOn-time69%
American AirlinesCheapest$254Average$383FlexibilityNo cancel feeOn-time71%

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