What is the cheapest airline that flies from Lambert-St Louis to Washington, D.C.?

Frontier, Southwest, and United Airlines are the most popular carriers operating from Lambert-St Louis to Washington, D.C.

How many flights depart from St. Louis to Washington, D.C. on average per week?

The number of flights available between St. Louis and Washington, D.C. is 82 per week as of April 2026. The most frequent departure day is Mon, with 21% of weekly flights leaving on this day.

What airlines fly to Washington, D.C.?

Southwest, American Airlines and United Airlines are the top three most popular airlines that fly to Washington, D.C. from St. Louis according to our data. Southwest is the first choice among our users, with 53% of people opting to fly with this airline when traveling to Washington, D.C.. Keep in mind that there are 5 different airlines that fly to Washington, D.C. on a routine basis, so you have a few additional options to choose from.

How many flights depart from St. Louis to Washington, D.C. on average per day?

The number of flights available between St. Louis and Washington, D.C. is 11 per day as of April 2026. The most frequent departure time is 12:00PM, with 48% of daily flights leaving in the afternoon.

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.?

The number of operators available for flights from Lambert-St Louis Airport to Washington, D.C. is 5 as of April 2026.

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.

$63 Cheap Flights from St. Louis to Washington, D.C. in 2026

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

Prices are currently low for flights on this route. Typical prices usually range from $434 to $262. The lowest price recently found on this route was $124.

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Discover deals from 900+ travel sites with momondo.

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

Round-trip

One-way

Last minute

Direct

Cheap round-trip flights

Enter your travel dates to find the best prices.

6:33 pm - 7:43 am

STL

BWI

12h 10m

1 stop

8:52 am - 5:33 pm

BWI

STL

9h 41m

1 stop

$124Frontier

Tue, May 26 - Tue, Jun 2

6:33 pm - 7:43 am

STL

BWI

12h 10m

1 stop

8:52 am - 5:33 pm

BWI

STL

9h 41m

1 stop

$126Frontier

Tue, May 26 - Tue, Jun 2

5:27 pm - 7:43 am

STL

BWI

13h 16m

1 stop

9:43 pm - 8:55 am

BWI

STL

12h 12m

1 stop

$127Frontier

Wed, Jun 3 - Sun, Jun 7

1:45 pm - 7:10 pm

STL

DCA

4h 25m

1 stop

11:45 am - 2:50 pm

DCA

STL

4h 05m

1 stop

$252Southwest

Tue, May 19 - Tue, Jun 9

7:45 am - 2:14 pm

STL

DCA

5h 29m

1 stop

11:57 am - 3:46 pm

DCA

STL

4h 49m

1 stop

$257United Airlines

Tue, May 19 - Wed, Jun 3

6:00 am - 12:19 pm

STL

DCA

5h 19m

1 stop

5:45 pm - 7:19 pm

DCA

STL

2h 34mnonstop

$260American Airlines

Wed, Jun 24 - Sat, Jun 27

9:23 am - 2:57 pm

STL

DCA

4h 34m

1 stop

8:00 pm - 9:29 pm

DCA

STL

2h 29mnonstop

$261American Airlines

Wed, May 27 - Mon, Jun 1

1:20 pm - 4:20 pm

STL

DCA

2h 00mnonstop

8:00 am - 9:20 am

DCA

STL

2h 20mnonstop

$265Southwest

Thu, May 21 - Mon, May 25

8:45 am - 11:55 am

STL

IAD

2h 10mnonstop

5:55 pm - 7:26 pm

IAD

STL

2h 31mnonstop

$265United Airlines

Tue, May 19 - Sat, May 23

6:04 pm - 10:59 pm

STL

DCA

3h 55m

1 stop

5:28 pm - 9:09 pm

DCA

STL

4h 41m

1 stop

$271Delta

Wed, May 27 - Mon, Jun 1

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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

May 19

STL7:45 amLambert-St Louis

5h 29m

1 stop

DCA2:14 pmWashington, D.C. Reagan-National

Jun 3

DCA11:57 amWashington, D.C. Reagan-National

4h 49m

1 stop

STL3:46 pmLambert-St Louis

$257

United Airlines

May 19

STL8:45 amLambert-St Louis

2h 10m

IAD11:55 amWashington, D.C. Dulles Intl

May 23

IAD5:55 pmWashington, D.C. Dulles Intl

2h 31m

STL7:26 pmLambert-St Louis

$265

United Airlines

Jun 30

STL8:43 amLambert-St Louis

2h 12m

IAD11:55 amWashington, D.C. Dulles Intl

Jul 14

IAD3:30 pmWashington, D.C. Dulles Intl

6h 56m

1 stop

STL9:26 pmLambert-St Louis

$286

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

Our best Delta deals on St. Louis to Washington, D.C. flight tickets

Delta

May 27

STL6:00 amLambert-St Louis

4h 39m

1 stop

IAD11:39 amWashington, D.C. Dulles Intl

Jun 1

IAD3:08 pmWashington, D.C. Dulles Intl

7h 30m

1 stop

STL9:38 pmLambert-St Louis

$271

Delta

May 21

STL7:01 pmLambert-St Louis

4h 50m

1 stop

IAD12:51 amWashington, D.C. Dulles Intl

May 25

IAD6:00 amWashington, D.C. Dulles Intl

4h 29m

1 stop

STL9:29 amLambert-St Louis

$285

Delta

Jun 15

STL6:10 pmLambert-St Louis

4h 04m

1 stop

IAD11:14 pmWashington, D.C. Dulles Intl

Jun 23

IAD8:29 amWashington, D.C. Dulles Intl

5h 05m

1 stop

STL12:34 pmLambert-St Louis

$296

momondo Fare Finder

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

Cheapest round-trip

St. LouisBaltimore

STL - BWI

STLBWI

Lambert-St Louis

Tue 5/26

6:33 pm-7:43 am

1 stop12h 10m

Baltimore/Washington

Tue 6/2

8:52 am-5:33 pm

1 stop9h 41m

$124

St. LouisBaltimore

STL - BWI

STLBWI

Lambert-St Louis

Tue 5/26

6:33 pm-7:43 am

1 stop12h 10m

Baltimore/Washington

Tue 6/2

8:52 am-5:33 pm

1 stop9h 41m

$126

St. LouisBaltimore

STL - BWI

STLBWI

Lambert-St Louis

Wed 6/3

5:27 pm-7:43 am

1 stop13h 16m

Baltimore/Washington

Sun 6/7

9:43 pm-8:55 am

1 stop12h 12m

$127

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Tue 5/19

1:45 pm-7:10 pm

1 stop4h 25m

Washington, D.C. Reagan-National

Tue 6/9

11:45 am-2:50 pm

1 stop4h 05m

$252

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Tue 5/19

7:45 am-2:14 pm

1 stop5h 29m

Washington, D.C. Reagan-National

Wed 6/3

11:57 am-3:46 pm

1 stop4h 49m

$257

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Wed 6/24

6:00 am-12:19 pm

1 stop5h 19m

Washington, D.C. Reagan-National

Sat 6/27

5:45 pm-7:19 pm

Nonstop2h 34m

$260

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Wed 5/27

9:23 am-2:57 pm

1 stop4h 34m

Washington, D.C. Reagan-National

Mon 6/1

8:00 pm-9:29 pm

Nonstop2h 29m

$261

Quickest round-trip

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Thu 5/21

1:20 pm-4:20 pm

Nonstop2h 00m

Washington, D.C. Reagan-National

Mon 5/25

8:00 am-9:20 am

Nonstop2h 20m

$265

St. LouisWashington, D.C.

STL - IAD

STLIAD

Lambert-St Louis

Tue 5/19

8:45 am-11:55 am

Nonstop2h 10m

Washington, D.C. Dulles Intl

Sat 5/23

5:55 pm-7:26 pm

Nonstop2h 31m

$265

St. LouisWashington, D.C.

STL - DCA

STLDCA

Lambert-St Louis

Wed 5/27

6:04 pm-10:59 pm

1 stop3h 55m

Washington, D.C. Reagan-National

Mon 6/1

5:28 pm-9:09 pm

1 stop4h 41m

$271

Flights are sorted by cheapest round-trip flights first.

Showing 1-10 of 20 resultsSorted by cheapest first

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

Prices

Airlines

Other information

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 $67. If you’re not able to fly to Washington, D.C. in August, then February is your next best option. Flight prices from St. Louis to Washington, D.C. during February average around $73.

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 $372. However, this price may fluctuate depending on the airline, the season, and holidays. When flying out on a Wednesday, 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 afternoon 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 $333. Flying to Washington, D.C. in the afternoon 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 $712. 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 Washington, D.C. Reagan-National for the best Lambert-St Louis - Washington, D.C. flight prices

How far in advance should I book a flight from St. Louis 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 $368 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 $236 on momondo.

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

You could potentially save up to 15% 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 April 2026, prices for St. Louis to Washington, D.C. flights are approximately 39% 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	$198
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 $198. The best round-trip flight deal from St. Louis to Washington, D.C. found on momondo in the last 72 hours is $328.

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).

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

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.?
The number of operators available for flights from Lambert-St Louis Airport to Washington, D.C. is 5 as of April 2026.
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.?
Based on momondo bookings for this flight route, the most popular plane model on flight routes from St. Louis to Washington, D.C. is Boeing 737 MAX 8 (25.13% of total bookings). The next most popular plane models are Canadair (Bombardier) Regional Jet 700 (19.04%), Canadair (Bombardier) Regional Jet 900 (18.97%), and Canadair (Bombardier) Regional Jet CRJ-550 (14.87%).
What is the most popular airline from St. Louis to Washington, D.C.?
Based on momondo bookings for flights between St. Louis and Washington, D.C., the leading airline is Southwest, making up 58% of the total bookings. Other popular airlines include American Airlines with 34%, Frontier with 6%, and Delta with 2%.

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
Frontier	PriceFrom $96	Free Cancellation	Rating 5.6 2,970 reviews	Search Frontier flights
Delta	PriceFrom $99	Free Cancellation	Rating 7.9 8,465 reviews	Search Delta flights
American Airlines	PriceFrom $172	Free Cancellation	Rating 7.1 11,678 reviews	Search American Airlines flights
Southwest	PriceFrom $197	Free Cancellation	Rating 8.0 4,314 reviews	Search Southwest flights
United Airlines	PriceFrom $264	Free Cancellation	Rating 7.4 9,680 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 $373, but momondo users have found Southwest deals from St. Louis to Washington, D.C. from as low as $197 round-trip. Southwest has been scored 8.0/10 in 4,314 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 $264, round-trip. It should be noted that an average United Airlines flight deal for this route in this time was higher, at $454 round-trip. United Airlines operates 10 flights out of St. Louis into Washington, D.C. in an average week, so prices vary by time and availability. 9,680 United Airlines reviews by users on momondo have scored the airline at 7.4/10.

Alexandria

National Harbor

Gettysburg

Arlington

Waldorf

Woodbridge

Laurel

Colonial Beach

Gaithersburg

Towson

Fredericksburg

Silver Spring

Rockville

Manassas

Linthicum Heights

Tysons

Bethesda

Springfield

Fairfax

College Park

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.

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

Washington, D.C. Reagan-National Airport

Washington, D.C. Dulles Intl Airport

Cheap flights from St. Louis to Washington, D.C. from $63

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 5/20. 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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United Airlines flights from St. Louis to Washington, D.C.

Our best United Airlines deals on St. Louis to Washington, D.C. flight tickets

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

Our best Delta deals on St. Louis to Washington, D.C. flight tickets

momondo Fare Finder

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

See travel insights to Washington, D.C. from

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

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.?

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

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

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

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

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

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

What is the cheapest airline that flies from Lambert-St Louis to Washington, D.C.?

What airlines fly to Washington, D.C.?

How many flights depart from St. Louis to Washington, D.C. on average per day?

How many flights depart from St. Louis to Washington, D.C. on average per week?

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

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

Fastest flight time

Direct flights

Airports in Washington, D.C.

Frequently asked questions about flying 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

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

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

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

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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.

Fly your favorite airline to Washington, D.C.

Airlines are sorted and displayed according to clicks in the past 7 days on momondo

Cabin classes currently available on flights to Washington, D.C.

List of cabin classes available on flights landing in Washington, D.C.. Availability may vary depending on flight origin and airline.

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