Cheap flights from Baltimore to St. Louis from $70

In general, October is the cheapest month to fly from Baltimore to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $174. The month of September is another great option to travel to St. Louis, with average flight prices from Baltimore averaging around $219.

The cheapest day to depart on your flight to St. Louis is on a Tuesday when prices can be found for as low as $329. 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 $415. 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 Baltimore in the evening is the least expensive time of day to depart. momondo users have found prices as low as $318 when looking at flights departing in the evening. In the afternoon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $387 per ticket.

Fly from Baltimore/Washington to Lambert-St Louis for the best Baltimore/Washington - Lambert-St Louis flight prices

You are more likely to see cheaper flights to St. Louis from Baltimore when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $356 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Baltimore for as low as $204 on momondo.

There is only 1 cabin class available to choose from on Baltimore/Washington to Lambert-St Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

Frontier and Delta are the most popular carriers operating from Baltimore/Washington to Lambert-St Louis

Southwest, American Airlines and Frontier are the top three most popular airlines that fly to St. Louis from Baltimore according to our data. Southwest is the first choice among our users, with 48% 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.

Atlanta (ATL) was the most common stop: 89% of momondo users choosing 1-stop flights on this route connected there.

Flights via Atlanta (ATL) offer the lowest average round-trip price of $156.

Flights connecting via Atlanta (ATL) have the shortest average one-way travel time: 4h 20m.

Atlanta (ATL) has the shortest average layover time for this route: 0h 56m.

The number of flights available between Baltimore and St. Louis is 3 per day as of March 2026. The most frequent departure time is 6:00AM, with 43% of daily flights leaving at noon.

The number of flights available between Baltimore and St. Louis is 22 per week as of March 2026. The most frequent departure day is Sun, with 27% of weekly flights leaving on this day.