Cheap flights from Phoenix to St. Louis from $103

In general, October is the cheapest month to fly from Phoenix to St. Louis. Due to it being the ‘off-season’ during this time, you can expect flight prices to be around $306. The month of January is another great option to travel to St. Louis, with average flight prices from Phoenix averaging around $309.

The cheapest day to depart on your flight to St. Louis is on a Friday when prices can be found for as low as $362. 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 $467. 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 Phoenix in the afternoon is the least expensive time of day to depart. momondo users have found prices as low as $346 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 $405 per ticket.

Fly from Phoenix Sky Harbor Intl to Lambert-St Louis for the best Phoenix - Lambert-St Louis flight prices

You are more likely to see cheaper flights to St. Louis from Phoenix when booking weeks ahead of your departure date. In general, you can expect to find flights to St. Louis for around $370 when searching weeks out. However, flight prices might be lower outside of this timeframe. For example, people recently found flights to St. Louis from Phoenix for as low as $307 on momondo.

There are 3 cabin classes available to choose from on Phoenix to St. Louis flights. Cabin price and availability will vary by airline so perform a search above to find the right deals for you.

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

Southwest, American Airlines and Frontier are the top three most popular airlines that fly to St. Louis from Phoenix according to our data. Southwest 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 3 different airlines that fly to St. Louis on a routine basis, so you have a few additional options to choose from.

7 flights are operational daily from Phoenix to St. Louis as of July 2026. The most popular departure time for this route is 8:00AM, with 39% of flights per day taking off at noon.

As of July 2026, 51 flights take off from Phoenix and land in St. Louis each week. The most common flight departure day for this route is Mon, with 18% of weekly flights taking off on this day.