Cheap flights from Phoenix to St. Louis from $86

In general, January 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 $309. The month of February is another great option to travel to St. Louis, with average flight prices from Phoenix averaging around $337.

The cheapest day to depart on your flight to St. Louis is on a Saturday when prices can be found for as low as $377. 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 $488. 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 $375 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 $484 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 $388 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 $356 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.

Frontier and Southwest 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 45% 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.

4 flights are operational daily from Phoenix to St. Louis as of November 2026. The most popular departure time for this route is 8:00AM, with 47% of flights per day taking off at noon.

As of November 2026, 30 flights take off from Phoenix and land in St. Louis each week. The most common flight departure day for this route is Sun, with 30% of weekly flights taking off on this day.