Cheap Flights from Washington (DCA) to St. Louis (CPS)

Popular airlines from Ronald Reagan Washington National Airport (DCA) to St. Louis, MO (CPS-St. Louis Downtown)

Alternative airports near St. Louis

Prices were available within the past 7 days. Prices and availability are subject to change.

Select flight to Lambert-St. Louis Intl. STL. Cheapest option available. Average driving time to city center is 20 minutes. Flights from $386
STL
Lambert-St. Louis Intl.
Cheapest
Average driving time to city center20 min
Flights from $386
Flights from Washington (DCA) to St. Louis (CPS)
Origin airport
Ronald Reagan Washington National
Destination airport
St. Louis Downtown
Distance
706 mi

Washington to St. Louis Flights

The cheapest times to fly from Washington to St. Louis

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Washington to St. Louis are during the month of . You can find some of the cheapest flights from Washington to St. Louis with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Washington to St. Louis

Sunday is one of the best days to book for cheap flights from Washington to St. Louis: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Washington to St. Louis

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Washington to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Washington to St. Louis flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Washington to St. Louis airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS) cost?
Lock in a cheap one-way flight or cheap return flight from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS) with Expedia. Enter your travel dates and sort by "Price (lowest to highest)" to see our cheapest flight offers on this route.
What is the cheapest month to fly from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS)?
The cheapest month to fly from DCA to CPS is , when there's less demand. Off-peak months are typically when better flight deals are available between these airports.
What is the cheapest airline that flies from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS)?
Expedia's filter tool lets you easily compare different airlines, travel time and fares all in one place. Choose your preferences, then sort by "Price (lowest to highest)" to see which carrier offers the cheapest DCA to CPS flight.
How many flights per day from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS)?
Direct flights from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS) aren't available daily, so you'll need to take a flight with a layover. Explore your options with Expedia's filter tool. Enter your dates and click on either "1 Stop" or "2+ Stops."
What day of the week has the most flights from DCA to CPS?
You'll typically find Tuesday the quietest day for flights, while Fridays are often the busiest.* However this can change from season to season and during peak travel times or public holidays.*Busiest/quietest day to travel is based on Expedia flight demand through January to December 2024.
What is the best time to fly from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS)?
Choose a flight from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS) that takes off before 3 PM to reduce the risk of cancellations and delays. Departures after this hour have a 22% higher chance of being canceled, on average.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG's global flight data platform.
What airports do you fly into for East St. Louis from Ronald Reagan Washington National Airport (DCA)?
Lambert-St. Louis Intl. Airport (STL) is the only airport in East St. Louis with direct flights from Ronald Reagan Washington National Airport (DCA). Check out your options and find affordable fares on Expedia.
Is it cheaper to buy a plane ticket from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS) last-minute?
Last-minute bookings from DCA to CPS are usually more expensive. To secure the lowest prices, start looking for flights early. That said, if you're flexible with your travel plans, it's possible to land a cheap ticket just before your departure.
Is it cheaper to book a DCA to CPS flight and hotel package?
Securing a DCA to CPS flight and hotel package is usually cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your travels in one place. Choose from our extensive range of hotels and then add flights, car rentals and activities to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Ronald Reagan Washington National Airport (DCA) to St. Louis Downtown Airport (CPS)?
If you booked your DCA to CPS flight in the last 24 hours, you may be able to modify or cancel it without fees. Depending on the airline and the ticket type you purchased, additional charges may apply for changes beyond that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal for further details.

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*Available to One Key members.