Cheap flights from Denver to St. Louis from $44

In general, January is the cheapest month to fly from Denver to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $175. The month of October is another great option to travel to St. Louis, with average flight prices from Denver averaging around $253.

The cheapest day to depart on your flight to St. Louis is on a Saturday when prices can be found for as low as $263. 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 $379. 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 Denver in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $264 when looking at flights departing in the afternoon. In the morning is when there is more demand to fly to St. Louis, so prices are often more expensive at around $332 per ticket.

Fly from Denver Intl to Lambert-St Louis for the best Denver Intl - Lambert-St Louis flight prices

You are more likely to see cheaper flights to St. Louis from Denver when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $286 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Denver for as low as $240 on momondo.

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

Frontier is the most popular carrier operating from Denver Intl to Lambert-St Louis

Frontier, United Airlines and Southwest are the top three most popular airlines that fly to St. Louis from Denver according to our data. Frontier is the first choice among our users, with 44% 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.

10 flights are operational daily from Denver to St. Louis as of September 2026. The most popular departure time for this route is 9:00AM, with 53% of flights per day taking off in the afternoon.

75 flights are operational weekly from Denver to St. Louis as of September 2026. The most popular departure day for this route is Mon, with 21% of flights per week taking off on this day.