HomeSearch by dateVacation packagesHotelsFlight dealsCar rentalTravel tips & news
St. Louis

$120+ 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 8/10. Fares are subject to change and may not be available on all flights or dates of travel.
IAD — STL
Jul 16 — Jul 231
Thu 7/16
Thu 7/23
1 adult, Economy
We work with more than 300 partners to bring you better travel deals

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

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.
Cheapflights Tip: The best prices from Washington, D.C. Dulles Intl to Lambert-St Louis are usually found in July or August, booked 48 days in advance, depart on a Saturday or Wednesday and return on a Tuesday

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 June 16, 2026.

This Kiwi.com deal was found by Cheapflights users on 6/12. 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 7/167:49 am
IAD
-
STL
1 stop10h 48m
Frontier
Fri 7/174:57 pm
STL
-
IAD
2 stops25h 41m
Frontier
Deal found 6/12$268
This Kiwi.com deal was found by Cheapflights users on 6/14. 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 8/197:30 am
IAD
-
STL
2 stops12h 53m
Frontier
Thu 8/208:21 pm
STL
-
IAD
1 stop10h 29m
Frontier
Deal found 6/14$269
This Trip.com deal was found by Cheapflights users on 6/15. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/119:30 am
IAD
-
STL
1 stop9h 45m
Frontier
Mon 7/134:57 pm
STL
-
IAD
1 stop4h 58m
Frontier
Deal found 6/15$270
This American Airlines deal was found by Cheapflights users on 6/12. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 8/67:57 am
IAD
-
STL
1 stop6h 05m
American Airlines
Mon 8/103:25 pm
STL
-
IAD
1 stop6h 30m
American Airlines
Deal found 6/12$271
This CheapOair deal was found by Cheapflights users on 6/13. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 7/141:32 pm
IAD
-
STL
1 stop11h 27m
Frontier
Thu 7/167:10 pm
STL
-
IAD
1 stop12h 10m
Frontier
Deal found 6/13$273
This Trip.com deal was found by Cheapflights users on 6/11. 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 Trip.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 7/127:49 am
IAD
-
STL
1 stop10h 48m
Frontier
Tue 7/214:09 pm
STL
-
IAD
1 stop17h 07m
Frontier
Deal found 6/11$274
This Frontier deal was found by Cheapflights users on 6/10. 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.
Thu 7/211:24 am
IAD
-
STL
1 stop7h 06m
Frontier
Tue 7/77:03 pm
STL
-
IAD
1 stop12h 17m
Frontier
Deal found 6/10$276
This Delta deal was found by Cheapflights users on 6/12. 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 6/306:05 am
IAD
-
STL
1 stop4h 27m
Delta
Fri 7/36:10 pm
STL
-
IAD
1 stop4h 04m
Delta
Deal found 6/12$277
This CheapOair deal was found by Cheapflights users on 6/13. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/239:50 am
IAD
-
STL
1 stop9h 25m
Frontier
Mon 7/274:57 pm
STL
-
IAD
1 stop4h 58m
Frontier
Deal found 6/13$278
This United Airlines deal was found by Cheapflights users on 6/13. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 12/58:20 am
IAD
-
STL
Nonstop2h 28m
United Airlines
Mon 12/76:45 pm
STL
-
IAD
1 stop4h 29m
United Airlines
Deal found 6/13$279
This CheapOair deal was found by Cheapflights users on 6/12. 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 CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 7/811:11 am
IAD
-
STL
1 stop13h 48m
Frontier
Sun 7/124:09 pm
STL
-
IAD
1 stop25h 24m
Frontier
Deal found 6/12$280
This Kiwi.com deal was found by Cheapflights users on 6/14. 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.
Tue 7/78:33 pm
IAD
-
STL
1 stop13h 24m
Frontier
Wed 7/88:08 pm
STL
-
IAD
2 stops15h 39m
Frontier
Deal found 6/14$282

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 June 16, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$268
(Kiwi.com)

One-way from

$120
(Frontier)

Popular in

June

Cheapest in

July

Average price

$636

Good round-trip deal

$408 or less

Good one-way deal

$242 or less
Provider with most accurate pricing for Washington, D.C. Dulles Intl-Lambert-St Louis flight deals.
Search Deals
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. 5% potential increase in price ($22 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 4% potential price decrease ($20 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in June 2026
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 June 16, 2026.
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

Fly to

Route

Depart

Return

Price

Cheapest round-trip

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Fri 7/3

6:00 pm-11:56 pm

1 stop6h 56m

Lambert-St Louis

Tue 7/7

10:19 am-4:41 pm

1 stop5h 22m

$277

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sat 7/4

8:29 am-12:34 pm

1 stop5h 05m

Lambert-St Louis

Sat 7/4

5:36 pm-12:44 am

1 stop6h 08m

$277

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 9/8

10:15 am-2:08 pm

1 stop4h 53m

Lambert-St Louis

Fri 9/11

1:40 pm-8:15 pm

1 stop5h 35m

$307
Quickest round-trip

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 6/30

10:05 pm-11:27 pm

Nonstop2h 22m

Lambert-St Louis

Tue 7/7

8:43 am-11:55 am

Nonstop2h 12m

$337

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Fri 8/14

7:26 pm-11:58 pm

1 stop5h 32m

Lambert-St Louis

Tue 8/18

6:00 am-11:33 am

1 stop4h 33m

$340

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Fri 7/31

5:42 pm-11:44 pm

1 stop7h 02m

Lambert-St Louis

Sun 8/2

8:43 am-11:55 am

Nonstop2h 12m

$369

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sat 9/5

8:25 am-9:39 am

Nonstop2h 14m

Lambert-St Louis

Mon 9/7

6:54 pm-12:44 am

1 stop4h 50m

$370

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sun 8/30

5:45 pm-7:11 pm

Nonstop2h 26m

Lambert-St Louis

Tue 9/1

5:30 pm-12:44 am

1 stop6h 14m

$399

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Fri 6/26

6:00 am-9:46 am

1 stop4h 46m

Lambert-St Louis

Wed 7/1

6:00 am-11:43 am

1 stop4h 43m

$405

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sun 7/26

8:15 am-12:11 pm

1 stop4h 56m

Lambert-St Louis

Wed 7/29

8:43 am-11:55 am

Nonstop2h 12m

$416

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/14

Showing 1-10 of 23 resultsSorted by cheapest first
1
2
3

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 June.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
eDreamsPrice Accuracy2 starsTrust Score*3 stars
JustAirTicketPrice Accuracy-Trust Score*1 star

*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 FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Washington, D.C. Dulles Intl Airport-St. Louis flight deals on Cheapflights vs. FlightHub >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 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 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?

The best time to book flights from Washington, D.C. Dulles Intl Airport to St. Louis is 47 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, July is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to St. Louis (average of $268). Flying from Washington, D.C. Dulles Intl Airport to St. Louis in June is currently the most expensive (average of $636). 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 June 16, 2026.

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

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

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
Our travel experts
Taryn White

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.

Read more
Ramsey Qubein

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.

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 June 16, 2026.
Get a feel of what it's like to fly with Delta,United Airlines, andFrontier 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
8,405 reviews

Food

7.2

Overall

7.9

Boarding

8.1

Crew

8.5

Comfort

7.8

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
Delta
7.9
Good
8,405 reviews
Delta
7.9
Good
8,405 reviews

Food

7.2

Overall

7.9

Boarding

8.1

Crew

8.5

Comfort

7.8

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
United Airlines
7.4
Good
9,842 reviews
Delta
7.9
Good
8,405 reviews

Food

7.2

Overall

7.9

Boarding

8.1

Crew

8.5

Comfort

7.8

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional
Frontier
5.6
Fair
2,882 reviews
Delta
7.9
Good
8,405 reviews

Food

7.2

Overall

7.9

Boarding

8.1

Crew

8.5

Comfort

7.8

Entertainment

7.8

Reviews

1 / 20
10.0
Excellent

Anonymous,May 2026

SEA - KOA

The snacks were not very good, not everyone was very friendly and professional

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 3 different airlines.

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

    Airlines like Delta and United Airlines fly from Washington, D.C. Dulles Intl Airport to St. Louis in about 2h 22m. The time it takes to get you to your destination can typically vary by up to 4h 34m. 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 $273. These flights start at 81% 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 ($60), American Airlines ($127), and Delta ($141).

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

    Consider Republic Airways (100%), Avianca (83%) or Copa Airlines (83%) 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 $720, our data indicates the cheapest price to be $197. The most popular route (Washington, D.C. Dulles Intl - Lambert-St Louis), is priced around $226.

  • 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, July is the cheapest month in which you can book a flight from Washington, D.C. Dulles Intl Airport to St. Louis (average of $268). Flying from Washington, D.C. Dulles Intl Airport to St. Louis in June is currently the most expensive (average of $636). 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
Fenton
Swansea
Fairview Heights
Eureka
Maryland Heights
Collinsville
Wentzville
Glencoe
Chesterfield
Alton
Farmington

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Top 3 airlines flying from Dulles Intl to St. Louis

Discover the top 3 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 June 16, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$78Average$223FlexibilityNo cancel feeOn-time62%
DeltaCheapest$124Average$292FlexibilityNo cancel feeOn-timeN/A
United AirlinesCheapest$273Average$544FlexibilityNo cancel feeOn-time69%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.