Cheap flights from Washington, D.C. to St. Louis from $53

In general, January is the cheapest month to fly from Washington, D.C. to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $344. The month of April is another great option to travel to St. Louis, with average flight prices from Washington, D.C. averaging around $352.

The cheapest day to depart on your flight to St. Louis is on a Wednesday when prices can be found for as low as $360. This is often the case because there is less demand to fly during this day of the week. If your travel schedule is flexible, try to avoid departing on a Sunday because tickets tend to average around $478. These prices are subject to change though, so be sure to set up a Price Alert for flights to St. Louis.

Flying to St. Louis from Washington, D.C. at noon is the least expensive time of day to depart. momondo users have found prices as low as $377 when looking at flights departing at noon. In the afternoon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $425 per ticket.

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

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

You could potentially save up to 4% on your flight if you consider stops on a Washington, D.C. to St. Louis flight.

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

Southwest, United Airlines and American Airlines are the top three most popular airlines that fly to St. Louis from Washington, D.C. 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 St. Louis. Keep in mind that there are 5 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

Denver (DEN) was the most common stop: 67% of momondo users choosing 1-stop flights on this route connected there.

Flights via Denver (DEN) offer the lowest average round-trip price of $270.

Flights connecting via Nashville (BNA) have the shortest average one-way travel time: 4h 25m.

Nashville (BNA) has the shortest average layover time for this route: 1h 10m.

As of September 2026, 9 flights take off from Washington, D.C. and land in St. Louis each day. The most common flight departure time for this route is 5:00PM, with 53% of daily flights taking off in the afternoon.

As of September 2026, there are 68 flights per week flying from Washington, D.C. to St. Louis. The most common day of the week flights depart is Mon, with 31% of flights taking off on this day.