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Cheap flights from St. Louis to Washington, D.C. from $59

This is the cheapest one-way flight price found by a momondo user in the last 72 hours by searching for a flight from St. Louis to Washington, D.C. departing on 9/4. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
1 adult
1 adult, Economy, 0 bags

Discover deals from 900+ travel sites with momondo.

Find the cheapest flights from St. Louis to Washington, D.C.

Cheap round-trip flights

Enter your travel dates to find the best prices.
Frontier Logo
6:45 pm - 8:04 amSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
12h 19m1 stop Las Vegas Harry Reid Intl
Frontier Logo
8:59 am - 5:50 pmIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
9h 51m1 stop Las Vegas Harry Reid Intl
$244Frontier
Fri, Aug 28 - Tue, Sep 1
Frontier Logo
6:45 pm - 8:04 amSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
12h 19m1 stop Las Vegas Harry Reid Intl
Frontier Logo
6:20 am - 5:22 pmIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
12h 02m1 stop Atlanta Hartsfield-Jackson
$244Frontier
Fri, Aug 28 - Mon, Aug 31
United Airlines Logo
8:40 am - 11:54 amSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
2h 14mnonstop
United Airlines Logo
8:25 am - 9:39 amIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
2h 14mnonstop
$244United Airlines
Sat, Sep 12 - Sat, Sep 19
United Airlines Logo
8:40 am - 11:54 amSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
2h 14mnonstop
United Airlines Logo
5:15 pm - 10:00 pmIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
5h 45m1 stop Chicago O'Hare Intl
$247United Airlines
Sun, Sep 6 - Sun, Sep 6
Delta Logo
7:20 pm - 12:42 amSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
4h 22m1 stop Atlanta Hartsfield-Jackson
Delta Logo
3:03 pm - 9:23 pmIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
7h 20m1 stop Atlanta Hartsfield-Jackson
$256Delta
Fri, Oct 16 - Tue, Oct 20
Delta Logo
5:59 pm - 11:14 pmSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
4h 15m1 stop Detroit Metropolitan Wayne County
Delta Logo
5:15 pm - 8:35 pmIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
4h 20m1 stop Detroit Metropolitan Wayne County
$256Delta
Fri, Sep 25 - Mon, Sep 28
American Airlines Logo
5:23 am - 12:52 pmSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
6h 29m1 stop Charlotte Douglas
American Airlines Logo
6:33 am - 11:56 amIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
6h 23m1 stop Charlotte Douglas
$257American Airlines
Sat, Sep 5 - Sun, Sep 6
American Airlines Logo
6:53 am - 11:56 amSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
4h 03m1 stop Charlotte Douglas
American Airlines Logo
6:14 am - 9:29 amIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
4h 15m1 stop Charlotte Douglas
$263American Airlines
Sat, Sep 26 - Mon, Sep 28
Multiple Airlines Logo
10:35 am - 12:28 amSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
12h 53m1 stop Atlanta Hartsfield-Jackson
Multiple Airlines Logo
6:36 pm - 12:41 amIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
31h 05m2 stops Blountville Tri Cities TN/VA Orlando
$285Multiple Airlines
Thu, Nov 19 - Mon, Nov 30
Multiple Airlines Logo
10:35 am - 5:36 pmSTL  Lambert-St Louis-IAD Washington, D.C. Dulles Intl
6h 01m1 stop Atlanta Hartsfield-Jackson
Multiple Airlines Logo
9:38 am - 11:59 pmIAD  Washington, D.C. Dulles Intl-STL Lambert-St Louis
15h 21m1 stop Seattle/Tacoma Intl
$425Multiple Airlines
Mon, Oct 19 - Sat, Oct 24

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Frontier flights from St. Louis to Washington, D.C. Dulles Intl Airport

Our best Frontier deals on St. Louis to Washington, D.C. Dulles Intl Airport flight tickets
Frontier
Aug 28
STL6:45 pmLambert-St Louis
12h 19m
1 stop
IAD8:04 amWashington, D.C. Dulles Intl
Aug 31
IAD6:20 amWashington, D.C. Dulles Intl
12h 02m
1 stop
STL5:22 pmLambert-St Louis
$244
Frontier
Sep 23
STL2:29 pmLambert-St Louis
8h 41m
1 stop
IAD12:10 amWashington, D.C. Dulles Intl
Sep 27
IAD11:12 amWashington, D.C. Dulles Intl
6h 22m
1 stop
STL4:34 pmLambert-St Louis
$252
Frontier
Nov 14
STL10:35 amLambert-St Louis
6h 01m
1 stop
IAD5:36 pmWashington, D.C. Dulles Intl
Nov 19
IAD9:16 pmWashington, D.C. Dulles Intl
11h 35m
1 stop
STL7:51 amLambert-St Louis
$255

United Airlines flights from St. Louis to Washington, D.C. Dulles Intl Airport

Our best United Airlines deals on St. Louis to Washington, D.C. Dulles Intl Airport flight tickets
United Airlines
Sep 6
STL8:40 amLambert-St Louis
2h 14m
IAD11:54 amWashington, D.C. Dulles Intl
Sep 6
IAD5:15 pmWashington, D.C. Dulles Intl
5h 45m
1 stop
STL10:00 pmLambert-St Louis
$247
United Airlines
Nov 14
STL8:30 amLambert-St Louis
2h 10m
IAD11:40 amWashington, D.C. Dulles Intl
Nov 19
IAD8:40 amWashington, D.C. Dulles Intl
2h 32m
STL10:12 amLambert-St Louis
$266
United Airlines
Sep 6
STL6:54 pmLambert-St Louis
4h 50m
1 stop
IAD12:44 amWashington, D.C. Dulles Intl
Sep 7
IAD8:20 amWashington, D.C. Dulles Intl
4h 42m
1 stop
STL12:02 pmLambert-St Louis
$268

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to Washington, D.C. Dulles Intl Airport 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, momondo users made 832,500 searches. Data last updated August 14, 2026.
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

Fri 8/28

6:45 pm-8:04 am

1 stop12h 19m

Washington, D.C. Dulles Intl

Tue 9/1

8:59 am-5:50 pm

1 stop9h 51m

$244

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Fri 8/28

6:45 pm-8:04 am

1 stop12h 19m

Washington, D.C. Dulles Intl

Mon 8/31

6:20 am-5:22 pm

1 stop12h 02m

$244
Quickest round-trip

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Sat 9/12

8:40 am-11:54 am

Nonstop2h 14m

Washington, D.C. Dulles Intl

Sat 9/19

8:25 am-9:39 am

Nonstop2h 14m

$244

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Sun 9/6

8:40 am-11:54 am

Nonstop2h 14m

Washington, D.C. Dulles Intl

Sun 9/6

5:15 pm-10:00 pm

1 stop5h 45m

$247

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Fri 10/16

7:20 pm-12:42 am

1 stop4h 22m

Washington, D.C. Dulles Intl

Tue 10/20

3:03 pm-9:23 pm

1 stop7h 20m

$256

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Fri 9/25

5:59 pm-11:14 pm

1 stop4h 15m

Washington, D.C. Dulles Intl

Mon 9/28

5:15 pm-8:35 pm

1 stop4h 20m

$256

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Sat 9/5

5:23 am-12:52 pm

1 stop6h 29m

Washington, D.C. Dulles Intl

Sun 9/6

6:33 am-11:56 am

1 stop6h 23m

$257

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Sat 9/26

6:53 am-11:56 am

1 stop4h 03m

Washington, D.C. Dulles Intl

Mon 9/28

6:14 am-9:29 am

1 stop4h 15m

$263

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Thu 11/19

10:35 am-12:28 am

1 stop12h 53m

Washington, D.C. Dulles Intl

Mon 11/30

6:36 pm-12:41 am

2 stops31h 05m

$285

St. LouisWashington, D.C.

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

STLIAD

Lambert-St Louis

Mon 10/19

10:35 am-5:36 pm

1 stop6h 01m

Washington, D.C. Dulles Intl

Sat 10/24

9:38 am-11:59 pm

1 stop15h 21m

$425

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first
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See travel insights to Washington, D.C. from

How to get the cheapest flight ticket from St. Louis to Washington, D.C. Dulles Intl Airport

Look no further. We've gone through all the searches for this route on momondo so you have the important information and insights to find the cheapest flight ticket for your trip

What is the typical price of a round-trip flight between St. Louis and Washington, D.C. Dulles Intl Airport?

Prices are currently low for flights on this route.

Typical prices usually range from $344 to $665.
The lowest price recently found on this route was $244.

What is the cheapest month to fly to Washington, D.C. Dulles Intl Airport?

In general, February is the cheapest month to fly from St. Louis to Washington, D.C. Dulles Intl Airport. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $170. If you aren’t able to travel to Washington, D.C. Dulles Intl Airport during the month of February, then flying in January is also cheap. Prices for this month can be found on momondo for an average of $352.

What is the cheapest day to depart on your flight to Washington, D.C. Dulles Intl Airport?

Our data shows that Wednesday is the least expensive day to fly to Washington, D.C. Dulles Intl Airport. Tickets to fly out on this day can be as low as $700. When flying out on a Thursday, the most expensive travel day of the week, you can expect to see flight prices from St. Louis to Washington, D.C. Dulles Intl Airport for around $1,157.

What is the cheapest time of day to depart on your flight to Washington, D.C. Dulles Intl Airport?

Flying to Washington, D.C. Dulles Intl Airport from St. Louis in the morning is the least expensive time of day to depart. momondo users have found prices as low as $824 when looking at flights departing in the morning. If you have a flexible travel schedule, then try to avoid flying at noon when prices are $1,141 on average. Flights to Washington, D.C. Dulles Intl Airport from St. Louis at noon are generally more expensive because this time of day is more convenient for travelers’ schedules.

What is the cheapest Lambert-St Louis to Washington, D.C. Dulles Intl flight route?

Fly from Lambert-St Louis to Washington, D.C. Dulles Intl for the best Lambert-St Louis - Washington, D.C. Dulles Intl flight prices

What cabin class options are available on St. Louis to Washington, D.C. Dulles Intl Airport flights?

There are 4 cabin classes available to choose from on St. Louis to Washington, D.C. Dulles Intl Airport flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Can stopping save me money on St. Louis to Washington, D.C. Dulles Intl Airport flights?

You could potentially save up to 11% on your flight if you consider stops on a St. Louis to Washington, D.C. Dulles Intl Airport flight.

How have St. Louis to Washington, D.C. Dulles Intl Airport flight prices changed over time?

As of August 2026, prices for St. Louis to Washington, D.C. Dulles Intl Airport flights are approximately 31% cheaper when compared to flights at the same time last year.

When to book flights from St. Louis to Washington, D.C. Dulles Intl Airport

Are you open to changing your travel dates? Check out the ideal times to fly from St. Louis to Washington, D.C. Dulles Intl Airport according to our flight data. Find out which month and days have the cheapest flights.
Estimated round-trip price

Cheap St. Louis to Washington, D.C. Dulles Intl Airport (STL to IAD) flight deals and tips

Find info about flight duration, direct flights, and airports for your flight from St. Louis to Washington, D.C. Dulles Intl Airport

Best Price Found

$246

Fastest flight time

2h 06m

Direct flights

Every day
The best one-way flight to Washington, D.C. Dulles Intl Airport from St. Louis in the past 72 hours is $246. The best round-trip flight deal from St. Louis to Washington, D.C. Dulles Intl Airport found on momondo in the last 72 hours is $873.
The fastest flight from St. Louis to Washington, D.C. Dulles Intl Airport takes 2h 06m
Direct flights go from St. Louis to Washington, D.C. Dulles Intl Airport every day.
Search flight deals

Frequently asked questions about flying from St. Louis to Washington, D.C. Dulles Intl Airport

  • How far is Lambert-St Louis to Washington, D.C. Dulles Intl by plane?

    The straight-line distance from Lambert-St Louis to Washington, D.C. Dulles Intl is 685.9 mi. Flights usually cover this in 2h 06m, depending on flying conditions and air traffic around both airports.

  • When did momondo last update prices for flights from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport?

    Prices for flights from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport are refreshed on a daily basis.

  • How many operators does momondo search for flights from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport?

  • How old do you have to be to fly from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport?

    Although the minimum age for a child to fly alone is five, airlines that offer an unaccompanied minor (UMNR) service may have their own age limits, which could be impacted by factors such as flight length, timing, and layovers. It is recommended that you verify with the airline you are booking with for travel from Lambert-St Louis Airport to Washington, D.C. Dulles Intl Airport.

  • What documentation or ID do you need to fly to Washington, D.C. Dulles Intl Airport?

    The necessary travel and health documents for your Washington, D.C. Dulles Intl Airport trip may vary depending on your travel plans and individual circumstances. Generally, you should have various documents, such as a national ID card or driver's license and a passport that is valid for six months beyond your scheduled arrival date. We recommend seeking advice from your airline or a trusted third party, such as IATA.

  • What is the most popular plane model from St. Louis to Washington, D.C. Dulles Intl Airport?

  • What is the most popular airline from St. Louis to Washington, D.C. Dulles Intl Airport?

Best airlines flying from St. Louis to Washington, D.C. Dulles Intl Airport

Compare and see reviews for airlines that fly from St. Louis to Washington, D.C. Dulles Intl Airport with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $90Free CancellationRating
5.6
2,695 reviews
Search Frontier flights
DeltaPriceFrom $98Free CancellationRating
7.8
8,503 reviews
Search Delta flights
American AirlinesPriceFrom $257Free CancellationRating
7.1
11,924 reviews
Search American Airlines flights
United AirlinesPriceFrom $271Free CancellationRating
7.4
10,112 reviews
Search United Airlines flights

  • United Airlines Flights From St. Louis to Washington, D.C. Dulles Intl Airport

    United Airlines flight deals from St. Louis to Washington, D.C. Dulles Intl Airport start from $271 round-trip. Over the 13 United Airlines flights for this route in a normal week, average airfare is usually $467 round-trip - but some users have found much cheaper deals with momondo.

Traveling to a place near Washington, D.C.?

Book flights to Washington, D.C. if you plan to visit one of these locations
Alexandria
National Harbor
Arlington
Gettysburg
Winchester
Waldorf
Laurel
Woodbridge
Fredericksburg
Gaithersburg
Linthicum Heights
Rockville
Silver Spring
Towson
Sterling
Colonial Beach
Springfield
Fairfax
Tysons
Edgewood

Why use momondo?

Why should I use momondo to find a flight deal from St. Louis to Washington, D.C.?

We help find the flight that best suits your needs, momondo compares prices from hundreds of airlines and travel agents and helps you filter them to find the best flight from St. Louis to Washington, D.C. for you.

Can I find flights from St. Louis to Washington, D.C. with flexible booking policies on momondo?

Yes. momondo allows you to filter the results for St. Louis to Washington, D.C. flights to just show those with flexible booking policies.

How can momondo help me find flights from St. Louis to Washington, D.C.?

momondo offers useful filters to help you find the right flight. Choose specific flight times, airports or even what payment method you prefer. We have numerous options to help you book your ideal flight from St. Louis to Washington, D.C..

I’m not ready to book a flight from St. Louis to Washington, D.C. right now. Can momondo alert me if prices change?

Yes. momondo can track prices for St. Louis to Washington, D.C. flights and alert you when they change. Perform a search to set up the price alert. All that is required is a valid email address.

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