Is Southwest the cheapest airline to fly with from Phoenix Sky Harbor Intl Airport to St. Louis?

With an average price of $406 return, Southwest is not the cheapest airline to fly from Phoenix Sky Harbor Intl Airport to St. Louis with. Instead, for the lowest price, our data suggests flying with Frontier, where a return flight costs $230 on average.

Does Southwest fly direct to St. Louis from Phoenix Sky Harbor Intl Airport?

Yes, Southwest does offer direct flights for the route, with around 6 flights per week.

What’s the cheapest day of the week to fly from Phoenix Sky Harbor Intl Airport to St. Louis with Southwest?

On average, the cheapest day of the week to fly from Phoenix Sky Harbor Intl Airport to St. Louis with Southwest is Wednesday, when prices are around $105. The most expensive day is generally Sunday, where the average price is around $177.

What’s the cheapest month to fly from Phoenix Sky Harbor Intl Airport to St. Louis with Southwest?

The cheapest month for Southwest flights to St. Louis from Phoenix Sky Harbor Intl Airport is generally October, where plane tickets cost $198 on average. If possible, try to avoid the most expensive months of February and January, where tickets cost $392 and $438 respectively.

$70 Cheap Southwest Flights from Phoenix Sky Harbor Intl Airport to St. Louis

PHX - STL

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Flight Deals

Cheap Southwest Flight Deals from Phoenix Sky Harbor Intl Airport to St. Louis

Here are some of the best deals found on KAYAK recently from Southwest for round-trip flights from Phoenix Sky Harbor Intl Airport to St. Louis that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.

Discover the best prices for you by selecting your travel dates on KAYAK.

Round-trip

One-way

Last minute

Direct

Recent round-trip Southwest flight deals from Phoenix Sky Harbor Intl Airport to St. Louis

Thu, Dec 4 - Mon, Dec 8

6:30 pm - 10:20 pmPHX-STL

2h 50mnonstop

5:25 pm - 7:50 pmSTL-PHX

3h 25mnonstop

$209Southwest

Find Deal

Fri, Nov 14 - Mon, Nov 17

6:30 am - 10:20 amPHX-STL

2h 50mnonstop

5:25 pm - 7:50 pmSTL-PHX

3h 25mnonstop

$213Southwest

Find Deal

Thu, Nov 13 - Sun, Nov 16

6:05 am - 12:10 pmPHX-STL

5h 05m1 stop

5:20 am - 7:45 amSTL-PHX

3h 25mnonstop

$223Southwest

Find Deal

Thu, Dec 11 - Sat, Dec 13

12:05 pm - 5:15 pmPHX-STL

4h 10m1 stop

1:25 pm - 3:50 pmSTL-PHX

3h 25mnonstop

$225Southwest

Find Deal

Mon, Dec 8 - Wed, Dec 10

4:40 pm - 8:30 pmPHX-STL

2h 50mnonstop

5:25 pm - 7:50 pmSTL-PHX

3h 25mnonstop

$228Southwest

Find Deal

Thu, Nov 27 - Thu, Dec 4

2:40 pm - 6:30 pmPHX-STL

2h 50mnonstop

8:15 pm - 10:40 pmSTL-PHX

3h 25mnonstop

$273Southwest

Find Deal

Thu, Nov 27 - Thu, Dec 4

2:40 pm - 6:30 pmPHX-STL

2h 50mnonstop

12:00 pm - 5:25 pmSTL-PHX

6h 25m1 stop

$283Southwest

Find Deal

Wed, Nov 26 - Mon, Dec 1

8:45 pm - 12:35 amPHX-STL

2h 50mnonstop

10:45 pm - 1:10 amSTL-PHX

3h 25mnonstop

$293Southwest

Find Deal

Tue, Nov 11 - Wed, Nov 12

8:25 am - 12:20 pmPHX-STL

2h 55mnonstop

5:25 pm - 7:50 pmSTL-PHX

3h 25mnonstop

$311Southwest

Find Deal

Wed, Jan 14 - Mon, Jan 19

1:20 pm - 5:10 pmPHX-STL

2h 50mnonstop

8:45 pm - 11:15 pmSTL-PHX

3h 30mnonstop

$317Southwest

Find Deal

Useful Info

Low season	January
High season	October
Cheapest flight	$70
Average price round-trip	$350

Best time to beat the crowds but there is an average 14% increase in price.

Most popular time to fly and prices are also 11% lower on average.

Flight from Phoenix to St. Louis

(price for this month)

When to Book Flights with Southwest from Phoenix Sky Harbor Intl Airport to St. Louis

Average price per month

Flight prices as travel date approaches

Is Southwest the cheapest airline to fly with from Phoenix Sky Harbor Intl Airport to St. Louis?
With an average price of $406 return, Southwest is not the cheapest airline to fly from Phoenix Sky Harbor Intl Airport to St. Louis with. Instead, for the lowest price, our data suggests flying with Frontier, where a return flight costs $230 on average.
What is the cheapest Southwest flight from Phoenix Sky Harbor Intl Airport to St. Louis?
In the last 3 days, the lowest price for a flight with Southwest from Phoenix Sky Harbor Intl Airport to St. Louis was $126 for a return flight and $70 for a one-way flight.
Does Southwest fly direct to St. Louis from Phoenix Sky Harbor Intl Airport?
Yes, Southwest does offer direct flights for the route, with around 6 flights per week.
What’s the cheapest day of the week to fly from Phoenix Sky Harbor Intl Airport to St. Louis with Southwest?
On average, the cheapest day of the week to fly from Phoenix Sky Harbor Intl Airport to St. Louis with Southwest is Wednesday, when prices are around $105. The most expensive day is generally Sunday, where the average price is around $177.
What’s the cheapest month to fly from Phoenix Sky Harbor Intl Airport to St. Louis with Southwest?
The cheapest month for Southwest flights to St. Louis from Phoenix Sky Harbor Intl Airport is generally October, where plane tickets cost $198 on average. If possible, try to avoid the most expensive months of February and January, where tickets cost $392 and $438 respectively.

8.0

Very good4,243 verified ratings

8.6Crew

8.1Boarding

8.0Comfort

7.5Entertainment

7.0Food

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Cons -

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10.0 Wonderful

James, Oct 2025

TUS-LAS

Very good

8.0 Very good

Greg, Oct 2025

OAK-BUR

Ever since Southwest starting charging for bags, passengers don't want to pay to check their bags, so the gate agents have to beg people to check their roller bags now because there's "not enough space". This was a terrible business move by Southwest.

8.0 Very good

Margaret, Oct 2025

SAV-HOU

Full cans of soda would be nice. A choice between two snacks would be appreciated.

8.0 Very good

TODD, Oct 2025

CMH-HOU

Tried watching free movie and it kept freezing so I couldn’t finish.

10.0 Wonderful

Antonio, Oct 2025

PVD-MCO

Always reliable

10.0 Wonderful

Verified traveler, Oct 2025

MDW-BWI

All was good. I just had a hard time getting connected to the WiFi/internet during the flight

4.0 Mediocre

Mike, Oct 2025

GRR-MDW

Staff/crew very good. 4 hour delay not good.

10.0 Wonderful

Stacy, Oct 2025

SMF-DEN

Sacrament staff are always polite and helpful. Airport is easy to maneuver and boarding is straightforward.

2.0 Poor

Verified traveler, Oct 2025

DAL-LIT

Delayed 5.5 hours

10.0 Wonderful

Verified traveler, Oct 2025

BOS-BWI

Great flight. Outstanding Service. Southwest was able to put us on a direct flight to Denver when the connection could have been affected by a later arrival to Baltimore. The direct flight was less expensive that the flight with the connection in Baltimore.

Everything you need to know for your flight from Phoenix Sky Harbor Intl Airport to St. Louis

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Cabin class types available on flights to St. Louis

First Class flights from Phoenix Sky Harbor Intl Airport to St. Louis

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PHX - STL

$70 Find Cheap Southwest Flights from Phoenix Sky Harbor Intl Airport to St. Louis

Search hundreds of travel sites at once for deals on Southwest flights from Phoenix Sky Harbor Intl Airport to St. Louis

Cheap Southwest Flight Deals from Phoenix Sky Harbor Intl Airport to St. Louis

Recent round-trip Southwest flight deals from Phoenix Sky Harbor Intl Airport to St. Louis

Recent one-way Southwest flight deals from Phoenix Sky Harbor Intl Airport to St. Louis

Recent last minute Southwest flight deals from Phoenix Sky Harbor Intl Airport to St. Louis

Recent direct Southwest flight deals from Phoenix Sky Harbor Intl Airport to St. Louis

Good to know

When to Book Flights with Southwest from Phoenix Sky Harbor Intl Airport to St. Louis

FAQs for flying to St. Louis with Southwest

Is Southwest the cheapest airline to fly with from Phoenix Sky Harbor Intl Airport to St. Louis?

What is the cheapest Southwest flight from Phoenix Sky Harbor Intl Airport to St. Louis?

Does Southwest fly direct to St. Louis from Phoenix Sky Harbor Intl Airport?

What’s the cheapest day of the week to fly from Phoenix Sky Harbor Intl Airport to St. Louis with Southwest?

What’s the cheapest month to fly from Phoenix Sky Harbor Intl Airport to St. Louis with Southwest?

Southwest Customer Reviews

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Everything you need to know for your flight from Phoenix Sky Harbor Intl Airport to St. Louis

Cabin class types available on flights to St. Louis

Cabin classes available on flights to Phoenix Sky Harbor Intl Airport. Prices are the lowest found on KAYAK over the last 7 days. Price and availability is not guaranteed.

Complete your trip to St. Louis with a hotel stay or car rental

Flights to other popular destinations

The most popular flights on KAYAK according to clicks in the last 2 weeks. Prices are the lowest found on KAYAK over the last 7 days. Price and availability is not guaranteed.

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Top Southwest flights

The most popular destinations for flights with Southwest according to clicks from KAYAK users. Prices are the lowest found on KAYAK over the last 7 days. Price and availability is not guaranteed.