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$77+ Cheap flights from Sky Harbor Intl (PHX) to St. Louis (STL)

This is the cheapest one-way flight price found by a Cheapflights user in the last 72 hours by searching for a flight departing on 9/18. Fares are subject to change and may not be available on all flights or dates of travel.
PHX — STL
Aug 25 — Sep 11
Mon 8/25
Mon 9/1
1 adult, Economy
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Cheapflights Tip: The best prices from Phoenix Sky Harbor Intl to Lambert-St Louis are usually found in September or August, booked 87 days in advance, depart on a Tuesday or Wednesday and return on a Wednesday

Cheap flight deals from Sky Harbor Intl to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Sky Harbor Intl (PHX) to St. Louis (STL). Learn about various techniques such as flexible date searches, comparing prices across and setting up price alerts. Use these methods to find the cheapest flights available for your travel needs. Data last updated August 20, 2025.

Round-trip from

$227
(Frontier)

One-way from

$77
(Mytrip)

Popular in

January

Cheapest in

September

Average price

$342

Good round-trip deal

$294 or less

Good one-way deal

$164 or less
From Phoenix Sky Harbor Intl to Lambert-St Louis
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One-way flight from Phoenix Sky Harbor Intl to Lambert-St Louis
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Highest demand for flights based on searches. 7% potential increase in price ($34 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($5 potential savings vs. average RT price).
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Average for round-trip flights in August 2025
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Price to beat on a round-trip flight from Phoenix Sky Harbor Intl to Lambert-St Louis.
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Price to beat on a one-way flight from Phoenix Sky Harbor Intl to Lambert-St Louis.
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Find flight deals from Sky Harbor Intl to St. Louis

Cheapest flights from Sky Harbor Intl to St. Louis
Explore the most affordable flight options available from Sky Harbor Intl to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 20, 2025.

This Booking.com deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/229:19 pmPHX - STL
1 stop9h 52mFrontier
Sun 8/247:54 pmSTL - PHX
1 stop26h 20mFrontier
Deal found 8/18$232
This Kiwi.com deal was found by Cheapflights users on 8/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/38:20 pmPHX - STL
1 stop10h 46mFrontier
Sun 10/54:00 pmSTL - PHX
2 stops31h 56mFrontier
Deal found 8/19$234
This Frontier deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 10/129:59 pmPHX - STL
1 stop9h 08mFrontier
Thu 10/232:47 pmSTL - PHX
1 stop10h 54mFrontier
Deal found 8/18$235
This CheapOair deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure CheapOair is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/48:40 pmPHX - STL
2 stops10h 26mFrontier
Sun 9/710:39 amSTL - PHX
2 stops12h 45mFrontier
Deal found 8/18$236
This Delta deal was found by Cheapflights users on 8/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/2112:40 amPHX - STL
1 stop6h 11mDelta
Wed 10/296:50 amSTL - PHX
1 stop7h 25mDelta
Deal found 8/19$237
This Kiwi.com deal was found by Cheapflights users on 8/19. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/38:20 pmPHX - STL
1 stop10h 46mFrontier
Mon 10/64:00 pmSTL - PHX
2 stops21h 14mFrontier
Deal found 8/19$238
This Southwest deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 10/215:10 amPHX - STL
Nonstop2h 50mSouthwest
Tue 10/215:20 pmSTL - PHX
1 stop5h 55mSouthwest
Deal found 8/18$239
This Kiwi.com deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/168:58 pmPHX - STL
2 stops10h 09mFrontier
Mon 10/207:52 pmSTL - PHX
1 stop17h 22mFrontier
Deal found 8/18$240
This Kiwi.com deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/184:14 pmPHX - STL
1 stop14h 53mFrontier
Wed 10/227:52 pmSTL - PHX
1 stop14h 07mFrontier
Deal found 8/18$241
This Kiwi.com deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Kiwi.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/157:30 pmPHX - STL
1 stop11h 37mFrontier
Sun 10/267:52 pmSTL - PHX
1 stop14h 07mFrontier
Deal found 8/18$242
This Booking.com deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Booking.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Tue 8/197:14 amPHX - STL
1 stop23h 57mFrontier
Thu 8/2110:17 amSTL - PHX
1 stop10h 37mFrontier
Deal found 8/18$243
This Delta deal was found by Cheapflights users on 8/18. Clicking the “Pick Dates” button in this card will allow you to select your dates and further customize your flight criteria. From there, click “Find deals”, make sure Delta is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 10/2212:40 amPHX - STL
1 stop6h 11mDelta
Sat 10/256:50 amSTL - PHX
1 stop7h 25mDelta
Deal found 8/18$244

Cheapflights Fare Finder

 
Customize your flight search to find flights from Sky Harbor Intl to St. Louis that fit within your specific budget. Explore options based on user searches and filter the results based on your desired price range. Find flights that match your budget for a cost-effective journey. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated August 20, 2025.
Use the filters below to find and compare flights from Phoenix Sky Harbor Intl Airport to St. Louis that are best for you.

Fly from

Sky Harbor Intl

Fly to

St. Louis

Route

Depart

Return

Price

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Sat 10/18

4:14 pm-9:07 am

1 stop14h 53m

Lambert-St Louis

Tue 10/21

7:52 pm-3:04 pm

1 stop21h 12m

$232

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Tue 9/30

8:00 am-9:06 am

1 stop23h 06m

Lambert-St Louis

Thu 10/9

10:17 am-9:39 am

2 stops25h 22m

$232

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Fri 10/17

9:59 pm-9:07 am

1 stop9h 08m

Lambert-St Louis

Sun 10/19

10:17 am-12:32 am

2 stops16h 15m

$234

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Fri 10/24

7:59 pm-9:07 am

1 stop11h 08m

Lambert-St Louis

Sun 10/26

10:17 am-12:32 am

2 stops16h 15m

$234

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Thu 10/16

8:58 pm-9:07 am

2 stops10h 09m

Lambert-St Louis

Wed 10/22

7:52 pm-7:59 am

1 stop14h 07m

$234

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Fri 10/3

8:20 pm-9:06 am

1 stop10h 46m

Lambert-St Louis

Sun 10/5

4:00 pm-9:56 pm

2 stops31h 56m

$234

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Mon 10/13

9:58 pm-9:07 am

2 stops9h 09m

Lambert-St Louis

Wed 10/22

7:52 pm-7:59 am

1 stop14h 07m

$234

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Sun 10/12

9:59 pm-9:07 am

1 stop9h 08m

Lambert-St Louis

Thu 10/23

2:47 pm-11:41 pm

1 stop10h 54m

$235

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Thu 10/23

6:00 am-10:37 am

1 stop26h 37m

Lambert-St Louis

Thu 10/30

11:07 am-10:40 pm

2 stops13h 33m

$235

PhoenixSt. Louis

PHX - STL

PHXSTL

Phoenix Sky Harbor Intl

Thu 9/4

8:40 pm-9:06 am

2 stops10h 26m

Lambert-St Louis

Sun 9/7

10:39 am-9:24 pm

2 stops12h 45m

$236

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/18

Showing 1-10 of 20 results
1
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The best insider tips for Phoenix Sky Harbor Intl Airport to St. Louis flights

Snippets provided in this section are AI-generated based on a summarization of Cheapflights-commissioned articles. The articles are presented as-is, for general informational purposes only, and may not be up-to-date. The opinions contained in the articles are original to the author and reflect their authentic experience, which may vary significantly from the experience of others.
Cheapflights partnered with top experts to bring you the best recommendations for your Phoenix Sky Harbor Intl Airport to St. Louis trip
Airports
PHX

PHX offers short security lines, typically under 10 minutes, ensuring a quick start to your journey to STL.

Read more about PHXby Brandon Schultz
STL

Use the MetroLink light rail from STL for a convenient, economical ride to downtown St. Louis in about 40 minutes.

Read more about STLby Taryn White
Our travel experts
Brandon Schultz

Brandon Schultz

Expert on PHX

Brandon Schultz

Brandon Schultz

Brandon Schultz is an award-winning food and travel writer based in New York City. His work has appeared in Forbes, AAA, Thrillist, Travel + Leisure, and The Daily Meal, among many others, and he is the author of 6 books, including 3 cookbooks.

Read more
Taryn White

Taryn White

Expert on STL

Taryn White

Taryn White

Taryn White is a freelance travel writer, digital creator, and travel advisor who has visited nearly 100 countries and all 50 states. She’s familiar with many airports and enjoys beach hopping, boutique hotels, spa experiences, and exploring local culture. Her work has appeared in Travel + Leisure, Condé Nast Traveler, National Geographic, Smithsonian Magazine, AFAR, and more.

Read more

Best time to book a flight from Sky Harbor Intl to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Sky Harbor Intl with our price prediction graph.
Estimated round-trip price
Rates are based on past data. Find the cheapest month and day to book your flight based on your travel requirements, then search for cheap deals.

Cheapflights Insights

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

How far ahead should I book a flight from Phoenix Sky Harbor Intl Airport to St. Louis?

Use this chart to determine the optimal time to book a round-trip flight from Sky Harbor Intl to St. Louis. Price data was last updated on August 8, 2025.

To ensure you get the cheapest price possible for a flight from Phoenix Sky Harbor Intl Airport to St. Louis, you should look to book at least 87 days in advance of your intended travel date. The price of your flight may increase if you delay and leave booking until a week or so before departure.

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

Currently, August is the cheapest month in which you can book a flight from Phoenix Sky Harbor Intl Airport to St. Louis (average of $311). Flying from Phoenix Sky Harbor Intl Airport to St. Louis in March is currently the most expensive (average of $356). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

What is the cheapest time of day to fly from PHX to STL?

Find hourly flight availability from Sky Harbor Intl to St. Louis. Discover flight options and departure times throughout the day, allowing you to choose a departure time that suits your schedule. Data last updated August 20, 2025.

A simple way to save on the total cost of your ticket is to fly from Phoenix Sky Harbor Intl Airport to St. Louis in the evening. If you’re flexible enough to do this you can expect to save up to 12% on your trip compared to booking a flight at noon.

What is the cheapest day to fly from Phoenix Sky Harbor Intl Airport to St. Louis?

Use this chart to determine the cheapest time to fly round-trip from Sky Harbor Intl to St. Louis. Price data was last updated on August 17, 2025.

Travelers seeking maximum savings on their Phoenix Sky Harbor Intl Airport to St. Louis flight should consider departing on Tuesday afternoons when fares are most often at their lowest. Sunday afternoons flights should be avoided if possible as fares are typically the most expensive at this time.

How much does it cost to fly round-trip from Phoenix Sky Harbor Intl Airport to St. Louis?

Reviews of airlines servicing St. Louis

Get insights into the airlines that provide service to St. Louis. Read reviews, discover amenities, and learn about the overall travel experience offered by airlines. Use this information to make informed decisions when choosing an airline for your flight to St. Louis. Reviews last updated August 20, 2025.
See what other customers who have flown with Southwest, Delta, and United Airlines from Phoenix Sky Harbor Intl Airport to St. Louis have to say. You can also see how each airline compares in terms of entertainment options, comfort, food, crew/service, and boarding process.
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Southwest
8.0
Very good
4,246 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Delta
8.0
Very good
7,982 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
United Airlines
7.4
Good
8,928 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.
Frontier
5.8
Fair
3,207 reviews
Southwest
8.0
Very good
4,246 reviews

Comfort

8.0

Overall

8.0

Boarding

8.1

Crew

8.6

Food

7.0

Entertainment

7.5

Reviews

1 / 20
8.0
Excellent

Walter,Aug 2025

OAK - SAN

Dozens of flights and I've never seen a row's beverages forgotten. I even went back and asked the attendant to check on them and nothing. I really hope it didn't have something to do with the Black mother with her kid in the row. Otherwise it was a typical Southwest flight, rapid boarding, tolerable leg room.

Related info for your journey

Find useful and relevant information for your journey from Sky Harbor Intl to St. Louis. Access travel guides, tips, and recommendations to enhance your travel experience. Get information about local attractions, weather, transportation options, and more.

  • What airport do you fly into for flights to St. Louis from Phoenix Sky Harbor Intl?

    Located just 12.7 mi from the city center, Lambert-St Louis is the airport most travelers will use when flying to St. Louis from Phoenix Sky Harbor Intl. Booking flights from Phoenix Sky Harbor Intl to Lambert-St Louis (STL) should be relatively easy as there are 5 daily inbound flights from Phoenix Sky Harbor Intl from 5 different airlines.

  • How long is the flight from Phoenix Sky Harbor Intl Airport to St. Louis?

    Departing from Phoenix Sky Harbor Intl Airport to St. Louis will take you 14h 53m. The distance between Phoenix Sky Harbor Intl Airport and St. Louis is about 1258 mi.

  • What are the cheapest airlines flying from Phoenix Sky Harbor Intl Airport to St. Louis round-trip?

    Currently priced at $116, Frontier will fly you from Phoenix Sky Harbor Intl Airport to St. Louis and back. In addition to Frontier, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from Delta and American Airlines - these airlines can fly you to your destination from $236 and $254, respectively. You may be able to fly from Phoenix Sky Harbor Intl Airport to St. Louis for 70% less than the average price by searching for these airlines.

  • What are the most reliable airlines from Phoenix Sky Harbor Intl Airport to St. Louis?

    Looking for the most reliable airlines to get you to your destination on time? Our data shows these are most likely to get you from Phoenix Sky Harbor Intl Airport to St. Louis on time: American Airlines (87%), Alaska Airlines (87%), SkyWest Airlines (86%).

  • What are the cheapest flights from Phoenix Sky Harbor Intl Airport to St. Louis?

    While on average a flight from Phoenix Sky Harbor Intl Airport to St. Louis is generally $283, our data shows the cheapest flight currently is $93. When looking at the most popular route, (Phoenix Sky Harbor Intl - Lambert-St Louis), you can expect to pay $161 for that flight.

  • Can I find deals for flights from Sky Harbor Intl to St. Louis that include hotel bookings?

    Yes. In addition to deals on Sky Harbor Intl to St. Louis flights, Cheapflights offers vacation packages that include both flights and hotel.

  • How can I find direct flights from Sky Harbor Intl to St. Louis?

    After entering your origin and destination, apply the non-stop filter on the search result page to find direct flights from Sky Harbor Intl to St. Louis.

  • Can I find deals for business class flights from Sky Harbor Intl to St. Louis?

    Yes. Cheapflights offers flight deals from Sky Harbor Intl to St. Louis by cabin class. In addition to browsing deals, you can also filter by cabin class on the search results page after making a search.

  • What is the cheapest month to book a flight from Phoenix Sky Harbor Intl Airport to St. Louis?

    Currently, August is the cheapest month in which you can book a flight from Phoenix Sky Harbor Intl Airport to St. Louis (average of $311). Flying from Phoenix Sky Harbor Intl Airport to St. Louis in March is currently the most expensive (average of $356). There are several factors that can impact the price of a flight, so comparing airlines, departure airports and flight times can provide users with more options.

See more FAQs

Traveling to a place near St. Louis?

Book flights to St. Louis if you plan to visit one of these locations
O'Fallon
Fairview Heights
Maryland Heights
Collinsville
Eureka
St. Peters
Glencoe
Alton
Chesterfield
Farmington
Festus

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Alternative routes for Sky Harbor Intl to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
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Top 5 airlines flying from Sky Harbor Intl to St. Louis

Discover the top 5 airlines that operate flights from Sky Harbor Intl to St. Louis. Compare their services, reliability, and customer satisfaction ratings to choose the airline that best suits your travel preferences and needs. Over the last 7 days, Cheapflights users made 2,558,603 searches. Data last updated August 20, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$116Average$223FlexibilityNo cancel feeOn-time62%
DeltaCheapest$236Average$352FlexibilityNo cancel feeOn-timeN/A
American AirlinesCheapest$254Average$415FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$273Average$453FlexibilityNo cancel feeOn-time69%
SouthwestCheapest$287Average$412FlexibilityNo cancel feeOn-time63%

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