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$84+ 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 8/21. Fares are subject to change and may not be available on all flights or dates of travel.
PHL — STL
Jul 26 — Aug 21
Sat 7/26
Sat 8/2
1 adult, Economy
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Cheapflights Tip: The best prices from Philadelphia to Lambert-St Louis are usually found in August or September, booked 80 days in advance, depart on a Wednesday or Tuesday and return on a Thursday

Cheap 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 21, 2025.

Round-trip from

$184
(Cheapflightsfares)

One-way from

$84
(Mytrip)

Popular in

May

Cheapest in

August

Average price

$359

Good round-trip deal

$247 or less

Good one-way deal

$164 or less
From Philadelphia to Lambert-St Louis
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One-way flight from Philadelphia to Lambert-St Louis
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Highest demand for flights based on searches. 10% potential increase in price ($43 potential increase over avg. RT price).
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Cheapest flight prices on average. 1% potential price decrease ($7 potential savings vs. average RT price).
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Average for round-trip flights in July 2025
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Price to beat on a round-trip flight from Philadelphia to Lambert-St Louis.
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Price to beat on a one-way flight from Philadelphia to Lambert-St Louis.
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Find 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 21, 2025.

This Cheapflightsfares deal was found by Cheapflights users on 7/20. 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 Cheapflightsfares is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sun 8/107:00 amPHL - STL
1 stop3h 52mSpirit Airlines
Fri 8/152:30 pmSTL - PHL
1 stop5h 19mSpirit Airlines
Deal found 7/20$184
This Southwest deal was found by Cheapflights users on 7/18. 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.
Sat 8/3011:30 amPHL - STL
Nonstop2h 25mSouthwest
Thu 9/47:25 pmSTL - PHL
Nonstop2h 10mSouthwest
Deal found 7/18$217
This FlightHub deal was found by Cheapflights users on 7/19. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/165:20 pmPHL - STL
1 stop7h 27mMultiple Airlines
Thu 8/212:30 pmSTL - PHL
1 stop5h 19mMultiple Airlines
Deal found 7/19$224
This American Airlines deal was found by Cheapflights users on 7/19. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/308:10 amPHL - STL
1 stop8h 39mAmerican Airlines
Mon 9/16:00 amSTL - PHL
Nonstop2h 18mAmerican Airlines
Deal found 7/19$227
This Delta deal was found by Cheapflights users on 7/19. 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.
Wed 8/134:59 pmPHL - STL
1 stop6h 03mDelta
Mon 8/181:26 pmSTL - PHL
1 stop6h 29mDelta
Deal found 7/19$237

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 21, 2025.
Use the filters below to find and compare flights from Philadelphia to St. Louis that are best for you.

Fly from

Philadelphia

Fly to

St. Louis

Route

Depart

Return

Price

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sun 8/10

7:00 am-9:52 am

1 stop3h 52m

Lambert-St Louis

Fri 8/15

2:30 pm-8:49 pm

1 stop5h 19m

$184

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 8/30

11:30 am-12:55 pm

Nonstop2h 25m

Lambert-St Louis

Thu 9/4

7:25 pm-10:35 pm

Nonstop2h 10m

$217

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 8/16

5:20 pm-11:47 pm

1 stop7h 27m

Lambert-St Louis

Thu 8/21

2:30 pm-8:49 pm

1 stop5h 19m

$224

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 8/30

8:10 am-3:49 pm

1 stop8h 39m

Lambert-St Louis

Mon 9/1

6:00 am-9:18 am

Nonstop2h 18m

$227

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Wed 8/13

4:59 pm-10:02 pm

1 stop6h 03m

Lambert-St Louis

Mon 8/18

1:26 pm-8:55 pm

1 stop6h 29m

$237

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 8/21

7:00 am-1:32 pm

1 stop7h 32m

$84

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Mon 8/18

7:30 pm-9:00 pm

Nonstop2h 30m

$109

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 10/21

7:00 am-10:40 am

1 stop4h 40m

$119

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 11/20

7:43 am-4:06 pm

1 stop9h 23m

$125

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 8/22

10:51 am-6:41 pm

2 stops8h 50m

$131

Flights are sorted by cheapest round-trip flights first.

Deals found on 7/19

Showing 1-10 of 12 results
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The best insider tips for Philadelphia 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 Philadelphia to St. Louis trip
Airlines
Southwest

Southwest offers free snacks and non-alcoholic beverages, enhancing the flight experience.


Enjoy free messaging and in-flight entertainment streamed to your device.

Read more about Southwestby Marisa Garcia
Frontier

Frontier offers extra comfort seats for a fee, ideal for flights around 3 hours.


Book early morning flights to avoid carry-over delays and ensure timely arrival.

Read more about Frontierby Marisa Garcia
Airports
PHL

For quick check-in, verify your airline’s terminal before arriving. Terminals are spread out, and only B and C, and D and E are linked by indoor hallways.

Read more about PHLby Mark Chesnut
STL

Use the MetroLink light rail for a convenient, economical ride from STL to downtown St. Louis. It takes about 40 minutes and avoids traffic.

Read more about STLby Taryn White
Our travel experts
Marisa Garcia

Marisa Garcia

Expert on Southwest and Frontier

Marisa Garcia

Marisa Garcia

Marisa knows planes inside and out, spending 16 years working on aircraft in hangars at airports around the world. She is an aviation industry expert, specialized in airline interiors and regulations. Ten years ago, she pivoted to journalism. She shares her insights in leading aviation, travel, and business publications and on her site FlightChic.

Read more
Mark Chesnut

Mark Chesnut

Expert on PHL

Mark Chesnut

Mark Chesnut

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

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 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?

Use this chart to determine the optimal time to book a round-trip flight from Philadelphia to St. Louis. Price data was last updated on July 18, 2025.

Booking 80 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, August is the cheapest month in which you can book a flight from Philadelphia to St. Louis (average of $311). Flying from Philadelphia 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 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 21, 2025.

It’s optimal to fly from Philadelphia to St. Louis at noon. By choosing this option you can save up to 9% 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 20, 2025.

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

Weekly flight availability from Philadelphia to St. Louis

Explore weekly flight availability from Philadelphia to St. Louis. Discover flights operating on different days of the week, giving you the flexibility to choose a travel day that best fits your plans. Compare info to find the most convenient option for your journey. Data last updated July 21, 2025.

The most flights from PHL to STL are scheduled on a Monday (9 on average). You will have fewer flight options on Tuesday, which is when the least amount of flights are scheduled (5 on average).

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 21, 2025.
See what other customers who have flown with Southwest, Delta, and American Airlines 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
4,232 reviews

Boarding

8.1

Food

7.0

Crew

8.6

Comfort

8.0

Entertainment

7.6

Overall

8.0

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Southwest
8.0
Very good
4,232 reviews
Southwest
8.0
Very good
4,232 reviews

Boarding

8.1

Food

7.0

Crew

8.6

Comfort

8.0

Entertainment

7.6

Overall

8.0

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Delta
8.0
Very good
7,962 reviews
Southwest
8.0
Very good
4,232 reviews

Boarding

8.1

Food

7.0

Crew

8.6

Comfort

8.0

Entertainment

7.6

Overall

8.0

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
American Airlines
7.2
Good
10,000 reviews
Southwest
8.0
Very good
4,232 reviews

Boarding

8.1

Food

7.0

Crew

8.6

Comfort

8.0

Entertainment

7.6

Overall

8.0

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Spirit Airlines
6.3
Okay
8,029 reviews
Southwest
8.0
Very good
4,232 reviews

Boarding

8.1

Food

7.0

Crew

8.6

Comfort

8.0

Entertainment

7.6

Overall

8.0

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.
Frontier
5.9
Fair
3,244 reviews
Southwest
8.0
Very good
4,232 reviews

Boarding

8.1

Food

7.0

Crew

8.6

Comfort

8.0

Entertainment

7.6

Overall

8.0

Reviews

1 / 20
8.0
Excellent

John,May 2025

PVD - BNA

It’s southwest so no frills but clean, efficient and got me to my location.

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 7 daily flights to St. Louis from 5 different airlines. 2h 20m 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 32 users in the past month. Keep an eye out for changes in search interest prior to high and low season.

  • 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 $184. Other airlines that can offer you cheap pricing are Southwest, from $217, and American Airlines, from $227. These flights start at 52% 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 Spirit Airlines, with whom users have recently found tickets for as low as $84. However, be on the lookout for offers from Southwest 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 (100%), Qatar Airways (76%) or American Airlines (73%) 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 $318, our data indicates the cheapest price to be $109. The most popular route (Philadelphia - Lambert-St Louis), is priced around $145.

  • 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, August is the cheapest month in which you can book a flight from Philadelphia to St. Louis (average of $311). Flying from Philadelphia 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
Maryland Heights
Fairview Heights
Collinsville
Eureka
St. Peters
Glencoe
Alton
Festus
Chesterfield
Farmington

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Alternative routes for Philadelphia to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
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Reagan-National to Columbia flights
State College to Springfield flights
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Allentown to Springfield flights
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Top 5 airlines flying from Philadelphia to St. Louis

Discover the top 5 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 21, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$48Average$191FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$144Average$183FlexibilityNo cancel feeOn-time65%
American AirlinesCheapest$199Average$388FlexibilityNo cancel feeOn-time71%
DeltaCheapest$216Average$417FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$281Average$416FlexibilityNo cancel feeOn-time63%

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