Cheap flights from Washington, D.C. Dulles Intl Airport to St. Louis from $128

In general, August is the cheapest month to fly from Washington, D.C. Dulles Intl Airport to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $312. The month of January is another great option to travel to St. Louis, with average flight prices from Washington, D.C. Dulles Intl Airport averaging around $349.

The cheapest day to depart on your flight to St. Louis is on a Wednesday when prices can be found for as low as $343. 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 Monday because tickets tend to average around $440. 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. Dulles Intl Airport at noon is the least expensive time of day to depart. momondo users have found prices as low as $358 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 $408 per ticket.

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

You are more likely to see cheaper flights to St. Louis from Washington, D.C. Dulles Intl Airport when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $442 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Washington, D.C. Dulles Intl Airport for as low as $312 on momondo.

There are 4 cabin classes available to choose from on Washington, D.C. Dulles Intl Airport 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 6% on your flight if you consider stops on a Washington, D.C. Dulles Intl Airport to St. Louis flight.

As of June 2026, prices for Washington, D.C. Dulles Intl Airport to St. Louis flights are approximately 44% more expensive when compared to flights at the same time last year.

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

United Airlines, Delta and Frontier are the top three most popular airlines that fly to St. Louis from Washington, D.C. Dulles Intl Airport according to our data. United Airlines is the first choice among our users, with 75% of people opting to fly with this airline when traveling to St. Louis. Keep in mind that there are 4 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

As of June 2026, 8 flights take off from Washington, D.C. Dulles Intl Airport and land in St. Louis each day. The most common flight departure time for this route is 5:00PM, with 62% of daily flights taking off in the afternoon.

As of June 2026, there are 58 flights per week flying from Washington, D.C. Dulles Intl Airport to St. Louis. The most common day of the week flights depart is Tue, with 17% of flights taking off on this day.