Cheap flights from Colorado to St. Louis from $103

In general, December is the cheapest month to fly from Colorado to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $33. The month of October is another great option to travel to St. Louis, with average flight prices from Colorado averaging around $34.

The cheapest day to depart on your flight to St. Louis is on a Friday when prices can be found for as low as $255. 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 $329. 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 Colorado in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $261 when looking at flights departing in the afternoon. At noon is when there is more demand to fly to St. Louis, so prices are often more expensive at around $327 per ticket.

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

You are more likely to see cheaper flights to St. Louis from Colorado when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $261 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Colorado for as low as $205 on momondo.

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

Delta, United Airlines, and American Airlines are the most popular carriers operating from Colorado to Lambert-St Louis

Frontier, United Airlines and Southwest are the top three most popular airlines that fly to St. Louis from Colorado according to our data. Frontier is the first choice among our users, with 43% 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.

13 flights are operational daily from Colorado to St. Louis as of June 2026. The most popular departure time for this route is 8:00PM, with 45% of flights per day taking off in the afternoon.

As of June 2026, 94 flights take off from Colorado and land in St. Louis each week. The most common flight departure day for this route is Thu, with 18% of weekly flights taking off on this day.