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Cheap flights from St. Louis to Washington, D.C. from $54

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 3/11. Fares may change, and may not be available for all flights or travel dates. Click the price to refresh the search for this deal.
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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
8:22 pm - 5:13 pm
STL
-
BWI
19h 51m
1 stop
Frontier Logo
6:00 am - 6:51 am
BWI
-
STL
25h 51m
1 stop
$131Frontier
Mon, Feb 23 - Sun, Mar 1
Frontier Logo
3:49 pm - 7:30 pm
STL
-
BWI
26h 41m
1 stop
Frontier Logo
5:58 pm - 6:51 am
BWI
-
STL
13h 53m
1 stop
$134Frontier
Tue, Feb 24 - Tue, Mar 3
American Airlines Logo
3:33 pm - 9:26 pm
STL
-
DCA
4h 53m
1 stop
American Airlines Logo
5:00 am - 8:35 am
DCA
-
STL
4h 35m
1 stop
$253American Airlines
Wed, Feb 18 - Sat, Feb 21
Delta Logo
10:14 am - 4:28 pm
STL
-
IAD
5h 14m
1 stop
Delta Logo
10:57 am - 3:56 pm
IAD
-
STL
5h 59m
1 stop
$253Delta
Wed, Feb 18 - Sat, Feb 21
American Airlines Logo
6:06 am - 9:12 am
STL
-
DCA
2h 06mnonstop
American Airlines Logo
1:44 pm - 3:18 pm
DCA
-
STL
2h 34mnonstop
$262American Airlines
Wed, Feb 18 - Mon, Mar 2
United Airlines Logo
12:15 pm - 3:27 pm
STL
-
IAD
2h 12mnonstop
United Airlines Logo
5:34 pm - 11:59 pm
IAD
-
STL
7h 25m
1 stop
$272United Airlines
Wed, Feb 18 - Mon, Mar 2
Southwest Logo
10:15 am - 6:00 pm
STL
-
DCA
6h 45m
2 stops
Southwest Logo
6:35 pm - 8:05 pm
DCA
-
STL
2h 30mnonstop
$277Southwest
Wed, Feb 18 - Mon, Mar 2
Delta Logo
6:32 am - 11:32 am
STL
-
IAD
4h 00m
1 stop
Delta Logo
12:14 pm - 4:32 pm
IAD
-
STL
5h 18m
1 stop
$277Delta
Tue, Mar 31 - Tue, Apr 7
Southwest Logo
7:25 pm - 10:20 pm
STL
-
DCA
1h 55mnonstop
Southwest Logo
3:35 pm - 6:55 pm
DCA
-
STL
4h 20m
1 stop
$280Southwest
Wed, Mar 18 - Mon, Mar 23
United Airlines Logo
9:55 am - 5:30 pm
STL
-
IAD
6h 35m
1 stop
United Airlines Logo
5:40 pm - 11:59 pm
IAD
-
STL
7h 19m
1 stop
$282United Airlines
Mon, Mar 2 - Tue, Mar 3

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

Our best United Airlines deals on St. Louis to Washington, D.C. flight tickets
United Airlines
Feb 18
STL12:15 pmLambert-St Louis
2h 12m
IAD3:27 pmWashington, D.C. Dulles Intl
Mar 2
IAD5:34 pmWashington, D.C. Dulles Intl
7h 25m
1 stop
STL11:59 pmLambert-St Louis
$272
United Airlines
Mar 2
STL9:55 amLambert-St Louis
6h 35m
1 stop
IAD5:30 pmWashington, D.C. Dulles Intl
Mar 3
IAD5:40 pmWashington, D.C. Dulles Intl
7h 19m
1 stop
STL11:59 pmLambert-St Louis
$282
United Airlines
Feb 21
STL8:30 amLambert-St Louis
2h 10m
IAD11:40 amWashington, D.C. Dulles Intl
Mar 6
IAD5:26 pmWashington, D.C. Dulles Intl
4h 41m
1 stop
STL9:07 pmLambert-St Louis
$284

Frontier flights from St. Louis to Washington, D.C.

Our best Frontier deals on St. Louis to Washington, D.C. flight tickets
Frontier
Feb 23
STL8:22 pmLambert-St Louis
19h 51m
1 stop
BWI5:13 pmBaltimore/Washington
Mar 1
BWI6:00 amBaltimore/Washington
25h 51m
1 stop
STL6:51 amLambert-St Louis
$131
Frontier
Feb 24
STL3:49 pmLambert-St Louis
26h 41m
1 stop
BWI7:30 pmBaltimore/Washington
Mar 3
BWI5:58 pmBaltimore/Washington
13h 53m
1 stop
STL6:51 amLambert-St Louis
$134
Frontier
Mar 6
STL1:09 pmLambert-St Louis
25h 49m
1 stop
BWI3:58 pmBaltimore/Washington
Mar 16
BWI5:31 amBaltimore/Washington
9h 03m
1 stop
STL1:34 pmLambert-St Louis
$136

momondo Fare Finder

 
Customize your flight search to find flights from St. Louis to Washington, D.C. 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 January 28, 2026.
Use the filters below to find and compare flights from St. Louis to Washington, D.C. that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

St. LouisBaltimore

STL - BWI

STLBWI

Lambert-St Louis

Mon 2/23

8:22 pm-5:13 pm

1 stop19h 51m

Baltimore/Washington

Sun 3/1

6:00 am-6:51 am

1 stop25h 51m

$131

St. LouisBaltimore

STL - BWI

STLBWI

Lambert-St Louis

Tue 2/24

3:49 pm-7:30 pm

1 stop26h 41m

Baltimore/Washington

Tue 3/3

5:58 pm-6:51 am

1 stop13h 53m

$134

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Wed 2/18

3:33 pm-9:26 pm

1 stop4h 53m

Washington, D.C. Reagan-National

Sat 2/21

5:00 am-8:35 am

1 stop4h 35m

$253

St. LouisWashington, D.C.

STL - IAD

STLIAD

Lambert-St Louis

Wed 2/18

10:14 am-4:28 pm

1 stop5h 14m

Washington, D.C. Dulles Intl

Sat 2/21

10:57 am-3:56 pm

1 stop5h 59m

$253

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Wed 2/18

6:06 am-9:12 am

Nonstop2h 06m

Washington, D.C. Reagan-National

Mon 3/2

1:44 pm-3:18 pm

Nonstop2h 34m

$262

St. LouisWashington, D.C.

STL - IAD

STLIAD

Lambert-St Louis

Wed 2/18

12:15 pm-3:27 pm

Nonstop2h 12m

Washington, D.C. Dulles Intl

Mon 3/2

5:34 pm-11:59 pm

1 stop7h 25m

$272

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Wed 2/18

10:15 am-6:00 pm

2 stops6h 45m

Washington, D.C. Reagan-National

Mon 3/2

6:35 pm-8:05 pm

Nonstop2h 30m

$277

St. LouisWashington, D.C.

STL - IAD

STLIAD

Lambert-St Louis

Tue 3/31

6:32 am-11:32 am

1 stop4h 00m

Washington, D.C. Dulles Intl

Tue 4/7

12:14 pm-4:32 pm

1 stop5h 18m

$277

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Wed 3/18

7:25 pm-10:20 pm

Nonstop1h 55m

Washington, D.C. Reagan-National

Mon 3/23

3:35 pm-6:55 pm

1 stop4h 20m

$280

St. LouisWashington, D.C.

STL - IAD

STLIAD

Lambert-St Louis

Mon 3/2

9:55 am-5:30 pm

1 stop6h 35m

Washington, D.C. Dulles Intl

Tue 3/3

5:40 pm-11:59 pm

1 stop7h 19m

$282

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.

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.?

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

The month of August is, on average, the cheapest month to fly to Washington, D.C. from St. Louis, with most prices found around $229. If you’re not able to fly to Washington, D.C. in August, then May is your next best option. Flight prices from St. Louis to Washington, D.C. during May average around $264.

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

On average, the least expensive day to fly to Washington, D.C. from St. Louis is on a Friday. momondo users have found tickets for Friday departures for as low as $359. However, this price may fluctuate depending on the airline, the season, and holidays. When flying out on a Sunday, the most expensive travel day of the week, you can expect to see flight prices from St. Louis to Washington, D.C. for around $479.

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

In the evening is the cheapest time of day to fly from St. Louis to Washington, D.C. when you can find flight prices for as low as $303. Flying to Washington, D.C. in the evening is an ideal time because this is during off-peak travel hours. Try not to purchase tickets at noon because they tend to be around $912. Of course, these prices can vary depending on the time of year and what airport you fly to.

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

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

How far in advance should I book a flight to Washington, D.C.?

You are more likely to see cheaper flights to Washington, D.C. from St. Louis when booking weeks ahead of your departure date. In general, you can expect to find flights to Washington, D.C. for around $379 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to Washington, D.C. from St. Louis for as low as $212 on momondo.

What cabin class options are available on Lambert-St Louis to Washington, D.C. flights?

There are 4 cabin classes available to choose from on Lambert-St Louis to Washington, D.C. 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. flights?

You could potentially save up to 44% on your flight if you consider stops on a St. Louis to Washington, D.C. flight.

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

As of January 2026, prices for St. Louis to Washington, D.C. flights are approximately 31% more expensive when compared to flights at the same time last year.

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

Are you open to changing your travel dates? Check out the ideal times to fly from St. Louis to Washington, D.C. 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. (STL to WAS) flight deals and tips

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

Best Price Found

$158

Fastest flight time

1h 55m

Direct flights

Every day

Airports in Washington, D.C.

2 airports
The best one-way flight to Washington, D.C. from St. Louis in the past 72 hours is $158. The best round-trip flight deal from St. Louis to Washington, D.C. found on momondo in the last 72 hours is $300.
The fastest flight from St. Louis to Washington, D.C. takes 1h 55m
Direct flights go from St. Louis to Washington, D.C. every day.
There are 2 airports in Washington, D.C.. From St. Louis there are direct flights to Washington, D.C. Reagan-National (DCA), Baltimore/Washington (BWI), Washington, D.C. Dulles Intl (IAD).
Search flight deals

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

    A flight from Lambert-St Louis to Washington, D.C. will travel around 708.3 mi. By plane, this route typically takes 1h 55m.

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

    Prices for flights from Lambert-St Louis Airport to Washington, D.C. are updated daily.

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

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

    The minimum age for a child to fly alone is five, but airlines that offer an unaccompanied minor (UNMR) service may have their own age limitations. Flight duration, scheduling, and layovers are among the considerations that may influence age limits. We recommend that you double-check with the airline you are booking with for travel from Lambert-St Louis Airport to Washington, D.C..

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

    The travel and health documents required for your trip to Washington, D.C. can vary based on your itinerary and personal situation. As a rule, consider having multiple documents such as a national ID card or driver’s license, and a passport valid for six-months after you plan to arrive at Washington, D.C.. We always recommend checking with your airline or a trusted third party such as IATA to get advice.

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

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

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

Compare and see reviews for airlines that fly from St. Louis to Washington, D.C. with momondo
Airline
Rating
Free Cancellation
Price
FrontierPriceFrom $73Free CancellationRating
5.7
3,056 reviews
Search Frontier flights
DeltaPriceFrom $99Free CancellationRating
7.9
8,124 reviews
Search Delta flights
American AirlinesPriceFrom $175Free CancellationRating
7.2
11,201 reviews
Search American Airlines flights
SouthwestPriceFrom $189Free CancellationRating
8.0
4,267 reviews
Search Southwest flights
United AirlinesPriceFrom $263Free CancellationRating
7.4
9,212 reviews
Search United Airlines flights

  • Southwest Flights From St. Louis to Washington, D.C.

    Southwest operates around 20 flights from St. Louis to Washington, D.C. every week. The average price of these flights found in the last 72 hours has been $348, but momondo users have found Southwest deals from St. Louis to Washington, D.C. from as low as $189 round-trip. Southwest has been scored 8.0/10 in 4,267 reviews.

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

    The best United Airlines deal for St. Louis to Washington, D.C. flight tickets found on momondo in the last 72 hours was $263, round-trip. It should be noted that an average United Airlines flight deal for this route in this time was higher, at $455 round-trip. United Airlines operates 14 flights out of St. Louis into Washington, D.C. in an average week, so prices vary by time and availability. 9,212 United Airlines reviews by users on momondo have scored the airline at 7.4/10.

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
Gettysburg
Arlington
Waldorf
Woodbridge
Tysons
Laurel
Colonial Beach
Silver Spring
Towson
Fredericksburg
Gaithersburg
Rockville
Manassas
Springfield
Fairfax
Linthicum Heights
Bethesda
Reston

Why use momondo?

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

momondo collates all your flight options in one place and lets you filter them to find the perfect flight from St. Louis to Washington, D.C.. momondo saves you time and could save you money on your trip.

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

Yes. All flights to Washington, D.C. from St. Louis on momondo can be compared and filtered by various policies on offer, including flexible booking.

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

momondo provides multiple filters to help you find the best flight to Washington, D.C. from St. Louis. Filter by price, airline, airports, cabin, aircraft, payment method, number of stops and more.

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

Of course. momondo tracks the price of St. Louis to Washington, D.C. flights. All you need is a valid email address and we will do the rest; it is that quick and easy.

An easier way to manage your Washington, D.C. trip

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Find better results for your trip to the United States

Fly into one of these airports located in Washington, D.C.

Airports listed have a maximum distance of 22.4 mi from Washington, D.C.
Washington, D.C. Reagan-National Airport
Washington, D.C. Dulles Intl Airport