$79 Cheap Flights from St. Louis (STL) to Phoenix (PHX)

View $79 flight on Mon, Aug 11, 2025Opens in a new window

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

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

Prices were available within the past 7 days and start at $79 for one-way flights and $157 for round trip, for the period specified. Prices and availability are subject to change. Additional terms apply.

Spirit Airlines
Thu, Jul 31 - Wed, Aug 6
STL
St. Louis
PHX
Phoenix
$157 Roundtrip, found 1 hour ago
$157
Roundtrip
found 1 hour ago
Select Spirit Airlines flight, departing Thu, Jul 31 from St. Louis to Phoenix, returning Wed, Aug 6, priced at $157 found 1 hour ago
Spirit Airlines
Fri, Aug 15 - Thu, Aug 21
STL
St. Louis
PHX
Phoenix
$161 Roundtrip, found 1 hour ago
$161
Roundtrip
found 1 hour ago
Select Spirit Airlines flight, departing Fri, Aug 15 from St. Louis to Phoenix, returning Thu, Aug 21, priced at $161 found 1 hour ago
Spirit Airlines
Mon, Aug 11 - Thu, Aug 14
STL
St. Louis
PHX
Phoenix
$167 Roundtrip, found 8 hours ago
$167
Roundtrip
found 8 hours ago
Select Spirit Airlines flight, departing Mon, Aug 11 from St. Louis to Phoenix, returning Thu, Aug 14, priced at $167 found 8 hours ago
Spirit Airlines
Fri, Jul 18 - Thu, Jul 24
STL
St. Louis
PHX
Phoenix
$171 Roundtrip, found 1 hour ago
$171
Roundtrip
found 1 hour ago
Select Spirit Airlines flight, departing Fri, Jul 18 from St. Louis to Phoenix, returning Thu, Jul 24, priced at $171 found 1 hour ago
Spirit Airlines
Sun, Aug 10 - Thu, Aug 14
STL
St. Louis
PHX
Phoenix
$172 Roundtrip, found 5 hours ago
$172
Roundtrip
found 5 hours ago
Select Spirit Airlines flight, departing Sun, Aug 10 from St. Louis to Phoenix, returning Thu, Aug 14, priced at $172 found 5 hours ago
Spirit Airlines
Thu, Jul 17 - Wed, Jul 23
STL
St. Louis
PHX
Phoenix
$174 Roundtrip, found 1 hour ago
$174
Roundtrip
found 1 hour ago
Select Spirit Airlines flight, departing Thu, Jul 17 from St. Louis to Phoenix, returning Wed, Jul 23, priced at $174 found 1 hour ago
Frontier Airlines
Mon, Aug 4 - Wed, Aug 6
STL
St. Louis
PHX
Phoenix
$183 Roundtrip, found 4 hours ago
$183
Roundtrip
found 4 hours ago
Select Frontier Airlines flight, departing Mon, Aug 4 from St. Louis to Phoenix, returning Wed, Aug 6, priced at $183 found 4 hours ago
Southwest Airlines
Thu, Aug 14 - Mon, Aug 18
STL
St. Louis
PHX
Phoenix
$257 Roundtrip, just found
$257
Roundtrip
just found
Select Southwest Airlines flight, departing Thu, Aug 14 from St. Louis to Phoenix, returning Mon, Aug 18, priced at $257 just found
American Airlines
Thu, Aug 14 - Mon, Aug 18
STL
St. Louis
PHX
Phoenix
$257 Roundtrip, just found
$257
Roundtrip
just found
Select American Airlines flight, departing Thu, Aug 14 from St. Louis to Phoenix, returning Mon, Aug 18, priced at $257 just found
United
Tue, Sep 9 - Mon, Sep 15
STL
St. Louis
PHX
Phoenix
$272 Roundtrip, found 1 hour ago
$272
Roundtrip
found 1 hour ago
Select United flight, departing Tue, Sep 9 from St. Louis to Phoenix, returning Mon, Sep 15, priced at $272 found 1 hour ago

Find the cheapest month to fly from St. Louis (STL) to Phoenix (PHX)

September is typically the cheapest month to fly

From $118 - $261 per traveler.

Graph displaying average flight prices per month

Flights from St. Louis (STL) to Phoenix (PHX)
Origin airport
Lambert-St. Louis Intl.
Destination airport
Sky Harbor Intl.
Airlines serving
Alaska Airlines, American Airlines, Delta, Frontier Airlines, Southwest Airlines, Spirit Airlines, United
Roundtrip price
$157
Distance
1259 mi
Average flight time
1 hour 46 mins

St. Louis to Phoenix Flights

The cheapest times to fly from St. Louis to Phoenix

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 St. Louis to Phoenix are during the month of July. You can find some of the cheapest flights from St. Louis to Phoenix with Expedia's search tool and vast selection of airlines.

 

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

Sunday is one of the best days to book for cheap flights from St. Louis to Phoenix: 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 St. Louis to Phoenix

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 St. Louis to Phoenix in 2025. You can also book with separate airlines for your outbound and return journeys, from $79 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 St. Louis to Phoenix 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 St. Louis to Phoenix 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 Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX) cost?
Cheap round-trip flights from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX) start from $197. 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 STL on July 26 2025 and touching down at PHX. The price was last updated on June 30 2025 and has not changed since.
What is the cheapest month to fly from STL to PHX?
Fly straight from STL to PHX in October to enjoy cheaper fares. You can find a one-way Southwest Airlines flight for $99 leaving on October 21 2025. This price is based on the cheapest direct flight found on Expedia for this route in the next 330 days. The price was last updated on June 30 2025 and remains unchanged.
Which airlines fly direct from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX)?
When jetting out of Lambert-St. Louis Intl. Airport (STL), you can get on a nonstop flight to Sky Harbor Intl. Airport (PHX) with Southwest Airlines.
What is the cheapest airline that flies from STL to PHX?
At the moment, the cheapest carrier offering one-way flights from STL to PHX is Southwest Airlines. You can jet off on this route from $99. This fare is based on the lowest price found on Expedia departing within the next three months. The flight takes off from STL on September 11 2025. Prices were last updated on June 30 2025 and have not changed since.
How many flights per day from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX)?
When jetting out of Lambert-St. Louis Intl. Airport (STL), you'll have your pick from an average of 6 daily nonstop flights to Sky Harbor Intl. Airport (PHX).
What are the most popular departure times for flights from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX)?
Flights between STL and PHX tend to be busiest at 2 PM. For a more relaxed trip and potentially cheaper prices, choose a departure outside the usual busy windows.
What day of the week has the most flights from STL to PHX?
Depart on a Friday if you're after the best choice of flights from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX).
What is the earliest flight from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX)?
Lambert-St. Louis Intl. Airport (STL)'s first flight to Sky Harbor Intl. Airport (PHX) leaves at approximately 6:00AM UTC-6. With a travel time of 3h 40m, you'll touch down at around 8:40AM UTC-7.
How long does it take to fly from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX)?
Flights from STL to PHX have an average travel time of 3 hours and 32 minutes. The total distance between the two airports is 1,250 mi.
What airline has the least delays from STL to PHX?
Consider booking with Frontier Airlines if you'd like to go straight from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX) without any holdups. This carrier has the strongest track record for punctuality, with an on-time score of 100%. Want to get notified of any changes? You can check your flight status using the Expedia App.
What is the best time to fly from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX)?
To avoid potential delays on the Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX) route, travel before 3 PM. Flights after this time have a 22% higher chance of cancellation.**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 Phoenix from Lambert-St. Louis Intl. Airport (STL)?
If you're on a direct flight from Lambert-St. Louis Intl. Airport (STL) to Phoenix, Sky Harbor Intl. Airport (PHX) is the only airport you can touch down at.
Is it cheaper to buy a plane ticket from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX) last-minute?
Holding off until right before your break to book your flight from STL to PHX generally means paying more. While you might find some last-minute offers, they're not always guaranteed. Be flexible with your itinerary for the best chance of landing a bargain.
Is it cheaper to book a STL to PHX flight and hotel package?
Compared with arranging hotels and flights separately, booking a STL to PHX flight and hotel package with Expedia could result in significant savings. Better yet, having everything in one easy place takes the hassle out of planning your trip. Just pick your flights and choose from our wide range of stays, then customize your trip with extras like tours and car rentals.
Can I cancel or change the date of my flight from Lambert-St. Louis Intl. Airport (STL) to Sky Harbor Intl. Airport (PHX)?
If you booked your STL to PHX flight within the last 24 hours, you may be able to modify or cancel it without fees. Depending on the airline and the type of fare you have, additional charges may apply for changes after that time. Airline policies and contact information can be found in your itinerary or confirmation email. Or, head to our Customer Service portal if you want more information.

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