$94 Cheap Flights from Phoenix (PHX) to St. Louis (STL)

View $94 flight on Sun, May 25, 2025Opens in a new window

Popular airlines from Phoenix Sky Harbor Intl. Airport (PHX) to St. Louis Lambert Intl. Airport (STL)

Cheap Flights from Phoenix to St. Louis (PHX-STL)

Prices were available within the past 7 days and start at $94 for one-way flights and $188 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Frontier Airlines
Sun, May 25 - Thu, May 29
PHX
Phoenix
STL
St. Louis
$188 Roundtrip, found 12 hours ago
$188
Roundtrip
found 12 hours ago
Select Frontier Airlines flight, departing Sun, May 25 from Phoenix to St. Louis, returning Thu, May 29, priced at $188 found 12 hours ago
Frontier Airlines
Tue, May 27 - Thu, May 29
PHX
Phoenix
STL
St. Louis
$197 Roundtrip, found 1 day ago
$197
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Tue, May 27 from Phoenix to St. Louis, returning Thu, May 29, priced at $197 found 1 day ago
Frontier Airlines
Thu, May 22 - Thu, May 29
PHX
Phoenix
STL
St. Louis
$207 Roundtrip, just found
$207
Roundtrip
just found
Select Frontier Airlines flight, departing Thu, May 22 from Phoenix to St. Louis, returning Thu, May 29, priced at $207 just found
Frontier Airlines
Thu, May 15 - Sat, May 17
PHX
Phoenix
STL
St. Louis
$218 Roundtrip, found 9 hours ago
$218
Roundtrip
found 9 hours ago
Select Frontier Airlines flight, departing Thu, May 15 from Phoenix to St. Louis, returning Sat, May 17, priced at $218 found 9 hours ago
Frontier Airlines
Sun, May 25 - Sun, May 25
PHX
Phoenix
STL
St. Louis
$221 Roundtrip, found 1 day ago
$221
Roundtrip
found 1 day ago
Select Frontier Airlines flight, departing Sun, May 25 from Phoenix to St. Louis, returning Sun, May 25, priced at $221 found 1 day ago
Southwest Airlines
Thu, May 22 - Thu, May 29
PHX
Phoenix
STL
St. Louis
$226 Roundtrip, just found
$226
Roundtrip
just found
Select Southwest Airlines flight, departing Thu, May 22 from Phoenix to St. Louis, returning Thu, May 29, priced at $226 just found
Frontier Airlines
Tue, Jun 3 - Sat, Jun 7
PHX
Phoenix
STL
St. Louis
$227 Roundtrip, found 6 hours ago
$227
Roundtrip
found 6 hours ago
Select Frontier Airlines flight, departing Tue, Jun 3 from Phoenix to St. Louis, returning Sat, Jun 7, priced at $227 found 6 hours ago
Frontier Airlines
Thu, May 8 - Sun, May 11
PHX
Phoenix
STL
St. Louis
$228 Roundtrip, found 1 hour ago
$228
Roundtrip
found 1 hour ago
Select Frontier Airlines flight, departing Thu, May 8 from Phoenix to St. Louis, returning Sun, May 11, priced at $228 found 1 hour ago
Frontier Airlines
Thu, May 15 - Thu, May 22
PHX
Phoenix
STL
St. Louis
$232 Roundtrip, found 3 hours ago
$232
Roundtrip
found 3 hours ago
Select Frontier Airlines flight, departing Thu, May 15 from Phoenix to St. Louis, returning Thu, May 22, priced at $232 found 3 hours ago
Southwest Airlines
Tue, Jun 3 - Sat, Jun 7
PHX
Phoenix
STL
St. Louis
$235 Roundtrip, found 6 hours ago
$235
Roundtrip
found 6 hours ago
Select Southwest Airlines flight, departing Tue, Jun 3 from Phoenix to St. Louis, returning Sat, Jun 7, priced at $235 found 6 hours ago
Flights from Phoenix (PHX) to St. Louis (STL)
Origin airport
Sky Harbor Intl.
Destination airport
Lambert-St. Louis Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Sun Country Airlines, United
Roundtrip price
$188
Distance
1259 mi

Phoenix to St. Louis Flights

The cheapest times to fly from Phoenix to St. Louis

On average, Thursday can be the cheapest time to fly, according to data from the Airlines Reporting Corporation (ARC), one of the world's biggest databases for global airline sales. The data reveals that you could save up to 16% by flying on a Thursday—the cheapest day to travel on average—instead of a Sunday—the most expensive. Some of the most affordable flights from Phoenix to St. Louis are during the month of May. You can find some of the cheapest flights from Phoenix to St. Louis with Expedia's search tool and vast selection of airlines.

 

The best time to book a flight from Phoenix to St. Louis

Sunday is one of the best days to book for cheap flights from Phoenix to St. Louis: Tickets reserved on a Sunday cost between 6% and 13% less than those reserved on a Friday, according to ARC data. The data also suggests booking early can also lead to cheaper airfares. You could save 24% by buying your tickets for domestic flights at least a month in advance and 10% by booking international flights 2 months in advance.

 

How to find cheap round-trip tickets from Phoenix to St. Louis

Being flexible with your dates and using Expedia's Price Drop Protection and Price Tracking features are some of the best ways of finding a cheap ticket from Phoenix to St. Louis in 2025. You can also book with separate airlines for your outbound and return journeys, from $94 one-way. Expedia also offers Price Drop Protection, so if the cost of your airfare goes down after booking, you'll receive a credit for the difference*. This is available for a small fee, and is free to One Key Gold and Platinum tier members.

 

Expedia's Price Tracking feature means you can stay on top of airfares without manually checking every day. It sends you automated price alerts for cheap Phoenix to St. Louis flights and uses historical data to indicate when the best time to book is. Download Expedia's free app to activate this handy tool in a few easy taps.

 

You could also save big by booking one of Expedia's vacation packages. Bundling together your Phoenix to St. Louis airfare with your accommodations and car rental is often cheaper than booking everything separately. There’s also One Key, Expedia's generous rewards program. Join for free and you could earn One Key cash on most bookings to save on future adventures.

 

*Terms apply.

 

Disclaimer: ARC The statistics are based on average round-trip ticket prices between January and August 2023. The percentages you see are averages.

 

Frequently asked questions

How much does a flight from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL) cost?
You can score cheap return fares from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL) starting at $319. Book a seat and be on your way. This information is based on the cheapest price found on Expedia for this return journey departing within the next three months. This airfare is for a Southwest Airlines flight leaving PHX on May 27 2025 and touching down at STL. The price was last updated on April 30 2025 and has not changed since.
What is the cheapest month to fly from PHX to STL?
The cheapest flights from PHX to STL are usually during off-peak season, when demand is lower. To save money, avoid flying during public holidays, school breaks and major local events.
Which airlines fly direct from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL)?
When setting off from Sky Harbor Intl. Airport (PHX), you can jump on a direct flight to Lambert-St. Louis Intl. Airport (STL) with Southwest Airlines.
What is the cheapest airline that flies from PHX to STL?
With fares starting at $160 for a one-way flight from PHX to STL, American Airlines is currently the cheapest carrier flying this route. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from PHX on July 16 2025. Prices were last updated on April 30 2025 and have not changed since.
How many flights per day from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL)?
With an average of 6 direct flights departing from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL) every day, you’ll be jetting off in no time.
What are the most popular departure times for flights from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL)?
The 9 AM departures from PHX to STL are the busiest. Greater demand means you’ll likely pay more for these departures. If you want to save on your trip, pick a less crowded time to fly.
What day of the week has the most flights from PHX to STL?
Depart on a Sunday if you’re looking for the largest selection of flights from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL).
What is the earliest flight from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL)?
Sky Harbor Intl. Airport (PHX)’s first flight to Lambert-St. Louis Intl. Airport (STL) departs at approximately 6:05AM UTC-7. With a travel duration of 2h 45m, you’ll touch down at around 9:50AM UTC-6.
How long does it take to fly from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL)?
Flights from PHX to STL have an average travel time of 2 hours and 59 minutes. The total distance between the two airports is 1,250 mi.
What airline has the least delays from PHX to STL?
With 100% of flights typically landing on time, Frontier Airlines has the best on-time performance for nonstop flights from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL). To check your flight status and receive notifications about any changes, use the Expedia App.
What is the best time to fly from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL)?
Opt for a flight from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL) that takes off before 3 PM to reduce the risk of delays and cancellations. Departures after this hour have a 22% higher chance of being canceled, on average.**Most reliable time of the day and month to travel recommendation is based on January through August 2024 flight status data sourced from OAG’s global flight data platform.
What airports do you fly into for St. Louis from Sky Harbor Intl. Airport (PHX)?
Lambert-St. Louis Intl. Airport (STL) is the only airport in St. Louis with direct flights from Sky Harbor Intl. Airport (PHX). Check out the available options and discover cheap fares on Expedia.
Is it cheaper to buy a plane ticket from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL) last-minute?
Booking your flight from PHX to STL shortly before your journey is typically more expensive. However, if there’s some wiggle room with your travel dates and times, you could snag a cheap last-minute fare.
Is it cheaper to book a PHX to STL flight and hotel package?
Opting for a PHX to STL flight and hotel package is generally cheaper than booking separately. With Expedia, you can enjoy the ease of organizing your trip all in one place. Choose from our wide range of stays and then add car rentals, flights and activities to your booking. Bundle it all together, and you could save hundreds of dollars.
Can I cancel or change the date of my flight from Sky Harbor Intl. Airport (PHX) to Lambert-St. Louis Intl. Airport (STL)?
In most instances, you can cancel or modify your PHX to STL flight. However, additional fees may apply, especially if your booking was made more than 24 hours ago. Check your itinerary for the airline’s policies and fees on flight changes, or if you’d like further details, head to our Customer Service portal.

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*Available to One Key members.