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$52+ Cheap flights from Philadelphia to St. Louis (PHL - 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 9/22. Fares are subject to change and may not be available on all flights or dates of travel.
PHL — STL
Aug 27 — Sep 31
Thu 8/27
Thu 9/3
1 adult, Economy
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Cheapflights Tip: The best prices from Philadelphia to Lambert-St Louis are usually found in September or August, booked 70 days in advance, depart on a Wednesday or Saturday and return on a Friday

Cheap flight deals from Philadelphia to St. Louis

Cheapest flights from Philadelphia to St. Louis
Explore the most affordable flight options available from Philadelphia to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on July 28, 2026.

This Kiwi.com deal was found by Cheapflights users on 7/24. 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 11/115:28 pm
PHL
-
STL
1 stop17h 12m
Frontier
Wed 11/1810:35 am
STL
-
PHL
1 stop6h 40m
Frontier
Deal found 7/24$110
This Kiwi.com deal was found by Cheapflights users on 7/23. 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 8/136:25 am
PHL
-
STL
1 stop12h 12m
Frontier
Mon 8/174:57 pm
STL
-
PHL
1 stop13h 18m
Frontier
Deal found 7/23$112
This Kiwi.com deal was found by Cheapflights users on 7/23. 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.
Sun 8/308:30 am
PHL
-
STL
1 stop9h 52m
Frontier
Mon 8/316:17 pm
STL
-
PHL
1 stop11h 58m
Frontier
Deal found 7/23$115
This Kiwi.com deal was found by Cheapflights users on 7/23. 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 8/276:30 am
PHL
-
STL
1 stop11h 52m
Frontier
Sun 8/306:17 pm
STL
-
PHL
1 stop11h 58m
Frontier
Deal found 7/23$120
This Kiwi.com deal was found by Cheapflights users on 7/23. 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 8/208:30 am
PHL
-
STL
1 stop9h 52m
Frontier
Thu 8/276:17 pm
STL
-
PHL
1 stop11h 58m
Frontier
Deal found 7/23$121
This Kiwi.com deal was found by Cheapflights users on 7/23. 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.
Sun 10/185:38 pm
PHL
-
STL
1 stop17h 02m
Frontier
Sun 10/2510:35 am
STL
-
PHL
1 stop20h 01m
Frontier
Deal found 7/23$123
This Kiwi.com deal was found by Cheapflights users on 7/23. 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.
Tue 8/118:30 am
PHL
-
STL
1 stop10h 07m
Frontier
Wed 8/124:57 pm
STL
-
PHL
1 stop13h 18m
Frontier
Deal found 7/23$129
This Kiwi.com deal was found by Cheapflights users on 7/23. 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 9/185:28 pm
PHL
-
STL
1 stop17h 12m
Frontier
Mon 9/2110:35 am
STL
-
PHL
1 stop20h 01m
Frontier
Deal found 7/23$136
This Kiwi.com deal was found by Cheapflights users on 7/27. 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 8/292:45 pm
PHL
-
STL
1 stop27h 37m
Frontier
Mon 8/316:17 pm
STL
-
PHL
1 stop11h 58m
Frontier
Deal found 7/27$160
This Kiwi.com deal was found by Cheapflights users on 7/27. 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 8/206:30 am
PHL
-
STL
1 stop11h 52m
Frontier
Mon 8/246:17 pm
STL
-
PHL
1 stop11h 58m
Frontier
Deal found 7/27$161

Find flight deals from Philadelphia to St. Louis

Discover tips and strategies to find the most affordable flight options for your journey from Philadelphia (PHL) 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 July 28, 2026.

Most accurate provider

FlightHub
3 stars

Most trusted provider

FlightHub
3 stars

Round-trip from

$110
(Kiwi.com)

One-way from

$52
(Kiwi.com)

Popular in

June

Cheapest in

September

Average price

$478

Good round-trip deal

$366 or less

Good one-way deal

$228 or less
Provider with most accurate pricing for Philadelphia-Lambert-St Louis flight deals.
Search Deals
Provider most trusted by Cheapflights users for Philadelphia-Lambert-St Louis flights.
Search Deals
From Philadelphia to Lambert-St Louis
Search Deals
One-way flight from Philadelphia to Lambert-St Louis
Search Deals
Highest demand for flights based on searches. 10% potential increase in price ($49 potential increase over avg. RT price).
Search Deals
Cheapest flight prices on average. 1% potential price decrease ($9 potential savings vs. average RT price).
Search Deals
Average for round-trip flights in July 2026
Search Deals
Price to beat on a round-trip flight from Philadelphia to Lambert-St Louis.
Search Deals
Price to beat on a one-way flight from Philadelphia to Lambert-St Louis.
Search Deals

Cheapflights Fare Finder

 
Customize your flight search to find flights from Philadelphia 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 July 28, 2026.
Use the filters below to find and compare flights from Philadelphia to St. Louis that are best for you.

Fly from

Fly to

Route

Depart

Return

Price

Cheapest round-trip
Quickest round-trip

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Mon 10/5

7:40 pm-9:00 pm

Nonstop2h 20m

Lambert-St Louis

Thu 10/8

7:50 pm-11:10 pm

Nonstop2h 20m

$277

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 9/17

6:20 am-7:35 am

Nonstop2h 15m

Lambert-St Louis

Mon 9/21

6:05 am-11:10 am

1 stop4h 05m

$287

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 8/25

2:45 pm-4:05 pm

Nonstop2h 20m

Lambert-St Louis

Tue 9/1

12:50 pm-8:55 pm

1 stop7h 05m

$287

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 8/25

1:45 pm-8:00 pm

2 stops7h 15m

Lambert-St Louis

Sat 8/29

8:25 am-2:40 pm

1 stop5h 15m

$302

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 9/3

11:45 am-7:05 pm

2 stops8h 20m

Lambert-St Louis

Sun 9/6

10:30 am-9:20 pm

2 stops9h 50m

$373

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 9/26

6:15 am-9:29 am

1 stop4h 14m

Lambert-St Louis

Sun 9/27

7:00 am-1:15 pm

1 stop5h 15m

$413

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 10/17

5:55 am-1:40 pm

2 stops8h 45m

Lambert-St Louis

Sun 10/18

2:05 pm-11:10 pm

2 stops8h 05m

$413

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 8/13

6:35 pm-8:00 pm

Nonstop2h 25m

Lambert-St Louis

Sat 8/15

5:45 am-11:15 am

1 stop4h 30m

$449

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 8/12

1:55 pm-10:10 pm

2 stops9h 15m

Lambert-St Louis

Tue 8/18

7:15 am-4:00 pm

2 stops7h 45m

$452

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Mon 8/10

12:45 pm-7:55 pm

2 stops8h 10m

Lambert-St Louis

Wed 8/12

7:15 am-4:00 pm

2 stops7h 45m

$469

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/27

Showing 1-10 of 21 resultsSorted by cheapest first
1
2
3

Compare providers for flights from Philadelphia to St. Louis

Provider information is updated monthly. Please note that these providers often have deals for this flight, but the availability may vary on a day-by-day basis on Cheapflights.
Use the table below to compare price accuracy, trust ratings, and cancellation policies for each provider offering flight deals from Philadelphia to St. Louis in July.
ProviderPrice AccuracyTrust Score*
ExpediaPrice Accuracy1 starTrust Score*3 stars
FlightHubPrice Accuracy3 starsTrust Score*3 stars
JustAirTicketPrice Accuracy-Trust Score*1 star

*The Trust Score is based on feedback from users after their booking experience. It measures overall satisfaction, helping us identify issues like hidden fees, problems during the ticketing process, and the quality of customer service. This score is our best indicator of the provider's quality and reliability.

  • Most accurate provider: When it comes to deals on Philadelphia-St. Louis flights, users find the pricing of FlightHub to be most consistent on Cheapflights vs. FlightHub Users can find the same prices on Philadelphia-St. Louis flight deals on Cheapflights vs. FlightHub >95% of the time. Price accuracy is based on data collected from Philadelphia-St. Louis flight searches over the past month and is updated monthly.
  • Most trusted provider: When it comes to deals on Philadelphia-St. Louis flights, Cheapflights users trust FlightHub the most. FlightHub has received a user feedback score of 3 out of 3 stars (3 being the best), meaning they have been trusted the most by Cheapflights users looking for Philadelphia-St. Louis flight deals. Provider user feedback score is based on Cheapflights searches over the past month and is updated monthly.

Best time to book a flight from Philadelphia to St. Louis

Have a flexible travel schedule? Discover the best time to fly to St. Louis from Philadelphia 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 Philadelphia to St. Louis

How far ahead should I book a flight from Philadelphia to St. Louis?

Booking 69 days in advance of your planned departure date is, on average, the best time to get cheap flights from Philadelphia to St. Louis. The general trend is that the closer you book to the departure date, the more expensive your flight will be.

What is the cheapest month to book a flight from Philadelphia to St. Louis?

Currently, September is the cheapest month in which you can book a flight from Philadelphia to St. Louis (average of $309). Flying from Philadelphia to St. Louis in June is currently the most expensive (average of $497). 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 PHL to STL?

Find hourly flight availability from Philadelphia 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 July 28, 2026.

It’s optimal to fly from Philadelphia to St. Louis in the afternoon. By choosing this option you can save up to 13% on the cost of your flight, compared to a flight in the morning.

What is the cheapest day to fly from Philadelphia to St. Louis?

Use this chart to determine the cheapest time to fly round-trip from Philadelphia to St. Louis. Price data was last updated on July 25, 2026.

Travelers seeking maximum savings on their Philadelphia to St. Louis flight should consider departing on Friday 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 Philadelphia to St. Louis?

Airfare is below average for this route at the moment.

Philadelphia to St. Louis flights typically cost between $245 and $442 in November.
The cheapest round-trip price found within the last 5 days was $110 on Frontier (Nov 11-Nov 18).

The best insider tips for Philadelphia to St. Louis flights

AI-powered summary based on content written by travel experts. AI can make mistakes.
Cheapflights partnered with top experts to bring you the best recommendations for your Philadelphia to St. Louis trip
Our travel experts
Mark Chesnut

Mark Chesnut

Expert on PHL

Mark Chesnut is a travel writer and public speaker with more than 30 years of experience. The 2019 winner of the NLGJA Excellence in Travel Writing Award, Mark is the author of the book “Prepare for Departure” and has covered air travel for multiple top consumer and trade media outlets.

Read more
Taryn White

Taryn White

Expert on STL

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

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 July 28, 2026.
See what other customers who have flown with Southwest,American Airlines, andFrontier from Philadelphia 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
4,228 reviews

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Entertainment

7.5

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.
Southwest
8.0
Very good
4,228 reviews
Southwest
8.0
Very good
4,228 reviews

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Entertainment

7.5

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.
American Airlines
7.1
Good
11,839 reviews
Southwest
8.0
Very good
4,228 reviews

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Entertainment

7.5

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.
Frontier
5.6
Fair
2,753 reviews
Southwest
8.0
Very good
4,228 reviews

Food

7.0

Boarding

8.1

Overall

8.0

Comfort

8.0

Entertainment

7.5

Crew

8.6

Reviews

1 / 20
2.0
Mediocre

Anonymous,Feb 2025

MCO - STL

Cancelled at last minute, SWA unable to assist in formulating alternate plans. Wound up renting a car and driving 13 hours to beat bad weather forecast at home. Not SWA’s fault that there was significant bad weather across the country.

Related info for your journey

Find useful and relevant information for your journey from Philadelphia 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 airports do I use to fly from Philadelphia to St. Louis?

    Lambert-St Louis is the airport most travelers will use when flying to St. Louis from Philadelphia. Booking flights from Philadelphia (PHL) to Lambert-St Louis (STL) should be relatively easy as there are 5 daily flights to St. Louis from 3 different airlines. 2h 15m is how long a flight from Philadelphia to Lambert-St Louis will take if you book a nonstop flight.

  • How popular is this Philadelphia to St. Louis flight route?

    This flight path from Philadelphia to Lambert-St Louis was viewed by 41 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • How long is the flight from Philadelphia to St. Louis?

    Airlines like Southwest fly from Philadelphia to St. Louis in about 2h 20m. The time it takes to get you to your destination is usually consistent. The distance between Philadelphia and St. Louis is about 811 mi. All flights are typically nonstop.

  • What are the cheapest airlines flying from Philadelphia to St. Louis round-trip?

    Cheapflights users have booked flights from Philadelphia to St. Louis round-trip from $144. Other airlines that can offer you cheap pricing are American Airlines, from $248, and Southwest, from $251. These flights start at 65% lower than the current average price 3 months from now.

  • What are the cheapest airlines to fly from Philadelphia to St. Louis one-way?

    The cheapest airline one-way is Frontier, with whom users have recently found tickets for as low as $70. However, be on the lookout for offers from American Airlines and Delta, as they are both options that can get you from Philadelphia to St. Louis for a low price.

  • What are the most reliable airlines from Philadelphia to St. Louis?

    Consider PSA Airlines (88%), American Airlines (84%) or Iberia (80%) when booking your flight. These represent the most reliable airlines when flying from Philadelphia to St. Louis.

  • What are the cheapest flights from Philadelphia to St. Louis?

    Looking for the cheapest flight from Philadelphia to St. Louis? While on average our users pay $477, our data indicates the cheapest price to be $127. The most popular route (Philadelphia - Lambert-St Louis), is priced around $250.

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

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

  • How can I find direct flights from Philadelphia to St. Louis?

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

  • Can I find deals for business class flights from Philadelphia to St. Louis?

    Yes. Cheapflights offers flight deals from Philadelphia 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 Philadelphia to St. Louis?

    Currently, September is the cheapest month in which you can book a flight from Philadelphia to St. Louis (average of $309). Flying from Philadelphia to St. Louis in June is currently the most expensive (average of $497). 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
Edwardsville
O'Fallon
Fenton
Swansea
Fairview Heights
Eureka
Maryland Heights
Collinsville
Wentzville
Glencoe
Chesterfield
Farmington

Browse thousands of different options on Cheapflights for your next trip

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Top 3 airlines flying from Philadelphia to St. Louis

Discover the top 3 airlines that operate flights from Philadelphia 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 July 28, 2026.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$144Average$226FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$248Average$418FlexibilityNo cancel feeOn-time71%
SouthwestCheapest$251Average$444FlexibilityNo cancel feeOn-time63%

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