St. Louis

$81+ 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 10/18. Fares are subject to change and may not be available on all flights or dates of travel.
PHL — STL
oct. 15 — oct. 221
We work with more than 300 partners to bring you better travel deals

Find cheap flights from Philadelphia to St. Louis with Cheapflights

1. Tell us where you want to go

Enter your travel information like dates, passengers, trip type (one-way or round trip), and preferred cabin class then click “Find deals”

2. Select your favorite providers

We find the providers serving your travel needs. Choose up to four travel providers to compare side-by-side for flights, hotels, or car rentals.

3. Compare prices and book

Review each provider’s pricing and select the best option for you! Book through your favorite provider’s website for a seamless experience.

Cheapflights Tip: The best prices from Philadelphia to Lambert-St Louis are usually found in August or September, booked 64 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 septiembre 15, 2025.

Round-trip from

$220
(Kiwi.com)

One-way from

$81
(Cheapflightsfares)

Popular in

May

Cheapest in

August

Average price

$355

Good round-trip deal

$265 or less

Good one-way deal

$211 or less
From Philadelphia to Lambert-St Louis
One-way flight from Philadelphia to Lambert-St Louis
Highest demand for flights based on searches. 6% potential increase in price ($28 potential increase over avg. RT price).
Cheapest flight prices on average. 1% potential price decrease ($5 potential savings vs. average RT price).
Average for round-trip flights in September 2025
Price to beat on a round-trip flight from Philadelphia to Lambert-St Louis.
Price to beat on a one-way flight from Philadelphia to Lambert-St Louis.

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 septiembre 15, 2025.

This Frontier deal was found by Cheapflights users on 9/13. 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.
lun. 9/295:15 amPHL - STL
2 stops8h 47mFrontier
jue. 10/210:49 amSTL - PHL
2 stops13h 10mFrontier
Deal found 9/13$219
This Frontier deal was found by Cheapflights users on 9/14. 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.
lun. 9/295:15 amPHL - STL
1 stop10h 49mFrontier
jue. 10/911:32 amSTL - PHL
2 stops12h 41mFrontier
Deal found 9/14$220
This Frontier deal was found by Cheapflights users on 9/14. 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.
dom. 10/55:15 amPHL - STL
1 stop10h 49mFrontier
mié. 10/157:52 pmSTL - PHL
1 stop8h 27mFrontier
Deal found 9/14$221
This CheapOair deal was found by Cheapflights users on 9/13. 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.
dom. 9/215:15 amPHL - STL
1 stop10h 49mFrontier
dom. 9/284:00 pmSTL - PHL
2 stops23h 55mFrontier
Deal found 9/13$222
This Kiwi.com deal was found by Cheapflights users on 9/14. 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.
sáb. 9/279:50 pmPHL - STL
1 stop12h 50mMultiple Airlines
jue. 10/910:57 amSTL - PHL
1 stop23h 55mMultiple Airlines
Deal found 9/14$224
This Kiwi.com deal was found by Cheapflights users on 9/14. 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.
mié. 10/112:00 pmPHL - STL
1 stop22h 40mMultiple Airlines
jue. 10/910:57 amSTL - PHL
1 stop23h 55mMultiple Airlines
Deal found 9/14$225
This Frontier deal was found by Cheapflights users on 9/14. 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.
dom. 10/195:20 amPHL - STL
1 stop6h 17mFrontier
jue. 10/3011:07 amSTL - PHL
2 stops13h 10mFrontier
Deal found 9/14$226
This Frontier deal was found by Cheapflights users on 9/13. 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.
lun. 10/136:18 amPHL - STL
2 stops15h 03mFrontier
jue. 10/231:41 pmSTL - PHL
1 stop10h 32mFrontier
Deal found 9/13$227
This Kiwi.com deal was found by Cheapflights users on 9/14. 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.
vie. 10/245:12 pmPHL - STL
2 stops16h 55mFrontier
lun. 10/2710:18 amSTL - PHL
1 stop14h 30mFrontier
Deal found 9/14$228
This Frontier deal was found by Cheapflights users on 9/13. 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.
jue. 9/255:15 amPHL - STL
1 stop10h 49mFrontier
dom. 9/284:00 pmSTL - PHL
1 stop7h 57mFrontier
Deal found 9/13$229
This Frontier deal was found by Cheapflights users on 9/13. 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.
vie. 10/37:25 amPHL - STL
2 stops14h 12mFrontier
mar. 10/77:52 pmSTL - PHL
2 stops17h 25mFrontier
Deal found 9/13$230

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 septiembre 15, 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

dom. 9/28

10:03 pm-1:02 pm

2 stops15h 59m

Lambert-St Louis

sáb. 10/11

7:15 pm-9:32 am

1 stop13h 17m

$260

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

jue. 2/5

5:05 pm-6:40 pm

Nonstop2h 35m

Lambert-St Louis

mar. 2/17

6:25 am-12:35 pm

1 stop5h 10m

$266

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

mar. 10/21

6:30 pm-8:00 pm

Nonstop2h 30m

Lambert-St Louis

mar. 10/28

8:15 am-11:20 am

Nonstop2h 05m

$317

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

mar. 10/14

7:20 am-4:00 pm

1 stop9h 40m

Lambert-St Louis

mar. 10/21

8:15 am-11:20 am

Nonstop2h 05m

$327

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

mié. 10/8

6:50 am-10:26 am

1 stop4h 36m

Lambert-St Louis

mié. 10/15

1:40 pm-7:47 pm

1 stop5h 07m

$337

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

mié. 10/8

9:46 am-1:22 pm

1 stop4h 36m

Lambert-St Louis

mar. 10/14

6:14 pm-11:05 pm

1 stop3h 51m

$337

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

sáb. 10/11

11:15 am-12:50 pm

Nonstop2h 35m

Lambert-St Louis

lun. 10/13

8:15 pm-11:25 pm

Nonstop2h 10m

$351

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

jue. 11/13

7:40 am-9:10 am

Nonstop2h 30m

Lambert-St Louis

lun. 11/17

12:00 pm-3:05 pm

Nonstop2h 05m

$351

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

lun. 9/29

5:15 am-1:02 pm

1 stop8h 47m

$83

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

jue. 10/16

5:20 am-10:37 am

1 stop6h 17m

$83

Flights are sorted by cheapest round-trip flights first.

Deals found on 9/14

Showing 1-10 of 17 results
1
2

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
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
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 September 12, 2025.

Booking 64 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 septiembre 15, 2025.

It’s optimal to fly from Philadelphia to St. Louis in the afternoon. By choosing this option you can save up to 11% on the cost of your flight, compared to a flight at noon.

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 September 7, 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.

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 septiembre 15, 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.

Crew

8.6

Food

7.0

Comfort

8.0

Entertainment

7.5

Overall

8.0

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

Crew

8.6

Food

7.0

Comfort

8.0

Entertainment

7.5

Overall

8.0

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines
8.0
Very good

Crew

8.6

Food

7.0

Comfort

8.0

Entertainment

7.5

Overall

8.0

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

Crew

8.6

Food

7.0

Comfort

8.0

Entertainment

7.5

Overall

8.0

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

Crew

8.6

Food

7.0

Comfort

8.0

Entertainment

7.5

Overall

8.0

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

Crew

8.6

Food

7.0

Comfort

8.0

Entertainment

7.5

Overall

8.0

Boarding

8.1

Reviews

1 / 20
2.0
Mediocre

Mike,Aug 2025

OKC - AUS

AC was not adequate, even on a night flight. WiFi subpar even for the airlines

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 6 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?

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

    Airlines like Southwest fly from Philadelphia to St. Louis in about 2h 35m. 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 $95. Other airlines that can offer you cheap pricing are Frontier, from $119, and American Airlines, from $243. These flights start at 76% lower than the current average price 3 months from now.

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

    Consider Republic Airways (100%), Southwest (72%) or American Airlines (70%) 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 $307, our data indicates the cheapest price to be $146. The most popular route (Philadelphia - Lambert-St Louis), is priced around $176.

  • 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
Edwardsville
O'Fallon
Fairview Heights
Maryland Heights
Collinsville
Eureka
Glencoe
St. Peters
Chesterfield
Alton
Farmington
Festus

Browse thousands of different options on Cheapflights for your next trip

Toggle through the tabs below to find thousands of options on Cheapflights for your next trip.

Alternative routes for Philadelphia to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.

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 septiembre 15, 2025.
AirlineCheapestAverageFlexibilityOn-time
Spirit AirlinesCheapest$95Average$178FlexibilityNo cancel feeOn-time65%
FrontierCheapest$119Average$236FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$243Average$416FlexibilityNo cancel feeOn-time71%
DeltaCheapest$259Average$442FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$266Average$418FlexibilityNo cancel feeOn-time63%

100% Free

Cheapflights is completely free to use, so you can start saving the moment you arrive.

Book with Flexibility

Our users can plan ahead with confidence and find flights with no change fees

Travel Smart

Millions of people come to us for their flight needs every year. We help make travel planning easy by providing useful insights and data-driven graphs that can inform your decisions.