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$55+ 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 7/13. Fares are subject to change and may not be available on all flights or dates of travel.
PHL — STL
Jun 28 — Jul 51
Sat 6/28
Sat 7/5
1 adult, Economy
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Cheapflights Tip: The best prices from Philadelphia to Lambert-St Louis are usually found in August or July, 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 June 23, 2025.

Round-trip from

$323
(Mytrip)

One-way from

$55
(FlightHub)

Popular in

May

Cheapest in

August

Average price

$291

Good round-trip deal

$355 or less

Good one-way deal

$184 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. 5% potential increase in price ($22 potential increase over avg. RT price).
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Cheapest flight prices on average. 2% potential price decrease ($9 potential savings vs. average RT price).
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Average for round-trip flights in June 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 June 23, 2025.

This Southwest deal was found by Cheapflights users on 6/23. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/47:30 pmPHL - STL
Nonstop2h 30mSouthwest
Sun 9/79:35 amSTL - PHL
1 stop3h 50mSouthwest
Deal found 6/23$314
This American Airlines deal was found by Cheapflights users on 6/23. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 9/47:19 pmPHL - STL
Nonstop2h 47mAmerican Airlines
Sun 9/75:27 amSTL - PHL
1 stop4h 15mAmerican Airlines
Deal found 6/23$320
This Frontier deal was found by Cheapflights users on 6/23. 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 Frontier is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 6/268:28 amPHL - STL
1 stop11h 56mFrontier
Fri 6/272:27 pmSTL - PHL
1 stop14h 22mFrontier
Deal found 6/23$322
This Mytrip deal was found by Cheapflights users on 6/21. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 8/87:00 amPHL - STL
1 stop3h 52mSpirit Airlines
Sun 8/1010:47 amSTL - PHL
3 stops28h 29mSpirit Airlines
Deal found 6/21$323
This Mytrip deal was found by Cheapflights users on 6/22. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 7/106:13 amPHL - STL
3 stops28h 39mMultiple Airlines
Mon 7/149:50 amSTL - PHL
3 stops12h 40mMultiple Airlines
Deal found 6/22$334
This United Airlines deal was found by Cheapflights users on 6/21. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 7/126:30 amPHL - STL
1 stop5h 10mUnited Airlines
Sat 7/195:30 pmSTL - PHL
1 stop6h 00mUnited Airlines
Deal found 6/21$363
This Delta deal was found by Cheapflights users on 6/21. 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.
Sun 7/136:00 amPHL - STL
1 stop4h 33mDelta
Tue 7/156:40 amSTL - PHL
1 stop4h 05mDelta
Deal found 6/21$378

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 June 23, 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

Fri 8/8

7:00 am-9:52 am

1 stop3h 52m

Lambert-St Louis

Sun 8/10

10:47 am-4:16 pm

3 stops28h 29m

$323

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 11/7

1:54 pm-7:03 pm

1 stop6h 09m

Lambert-St Louis

Sun 11/9

6:43 am-9:50 am

Nonstop2h 07m

$331

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Thu 7/10

6:13 am-9:52 am

3 stops28h 39m

Lambert-St Louis

Mon 7/14

9:50 am-11:30 pm

3 stops12h 40m

$334

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sun 7/6

8:28 am-6:59 pm

1 stop11h 31m

Lambert-St Louis

Thu 7/10

2:27 pm-5:49 am

1 stop14h 22m

$341

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Fri 10/3

10:10 am-7:05 pm

2 stops9h 55m

Lambert-St Louis

Sun 10/5

3:40 pm-11:05 pm

1 stop6h 25m

$346

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sat 7/12

6:30 am-10:40 am

1 stop5h 10m

Lambert-St Louis

Sat 7/19

5:30 pm-12:30 am

1 stop6h 00m

$363

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sun 7/13

6:00 am-9:33 am

1 stop4h 33m

Lambert-St Louis

Tue 7/15

6:40 am-11:45 am

1 stop4h 05m

$378

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Sun 7/13

6:45 am-11:59 pm

1 stop18h 14m

Lambert-St Louis

Wed 7/23

6:00 am-5:55 pm

2 stops10h 55m

$8,139

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Mon 7/28

7:00 am-9:52 am

1 stop3h 52m

$58

PhiladelphiaSt. Louis

PHL - STL

PHLSTL

Philadelphia

Tue 9/2

3:45 pm-5:10 pm

Nonstop2h 25m

$99

Flights are sorted by cheapest round-trip flights first.

Deals found on 6/21

Showing 1-10 of 15 results
1
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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 June 20, 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 June 23, 2025.

It’s optimal to fly from Philadelphia to St. Louis at noon. By choosing this option you can save up to 11% 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 June 22, 2025.

Travelers seeking maximum savings on their Philadelphia to St. Louis flight should consider departing on Wednesday at noon 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 June 23, 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 (3 on average).

Rainfall in St. Louis by month

Plan your trip to St. Louis by taking into account the average rainfall totals by month.

In terms of precipitation, rainfall in St. Louis ranges from 2.2 - 4.7 inches per month. May is typically the wettest month, when rainfall can reach 4.7 in. February is typically the driest time to visit St. Louis when rainfall is around 2.2 in.

Temperature in St. Louis by month

Plan your trip to St. Louis by taking into account the average temperature totals by month.

If weather is an important factor for your trip to St. Louis, use this chart to help with planning. For those seeking warmer temperatures, July is the ideal time of year to visit, when temperatures reach an average of 80.6 F. Travelers looking to avoid the cold should look outside of January, when temperatures are typically at their lowest (around 32.0 F).

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 June 23, 2025.
To help decide which airline to fly from Philadelphia to St. Louis, see what other customers have to say about Alaska Airlines, Southwest and Delta. In addition to providing an overall rating, users have also rated airlines in terms of entertainment options, comfort, food, crew/service, and boarding process.
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Alaska Airlines
8.0
Very good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Southwest
8.0
Very good
4,278 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
Delta
8.0
Very good
7,966 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
United Airlines
7.4
Good
8,831 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.
American Airlines
7.2
Good
10,000 reviews
Alaska Airlines
8.0
Very good
10,000 reviews

Entertainment

7.1

Boarding

8.1

Food

7.1

Crew

8.5

Comfort

7.8

Overall

8.0

Reviews

1 / 20
10.0
Excellent

James,Apr 2025

LAX - SFO

Good flight except the uncontrollable cold air from the ceiling.

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 4 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 30 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 $323. Other airlines that can offer you cheap pricing are American Airlines, from $331, and Frontier, from $341. These flights start at 11% 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 $55. However, be on the lookout for offers from American Airlines and Southwest, 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 Qatar Airways (81%), Iberia (76%) or British Airways (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 $324, our data indicates the cheapest price to be $126. The most popular route (Philadelphia - Lambert-St Louis), is priced around $144.

  • 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 Philadelphia?

Book flights to Philadelphia 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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Top 4 airlines flying from Philadelphia to St. Louis

Discover the top 4 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 June 23, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$48Average$124FlexibilityNo cancel feeOn-time62%
American AirlinesCheapest$157Average$359FlexibilityNo cancel feeOn-time71%
DeltaCheapest$200Average$366FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$279Average$416FlexibilityNo cancel feeOn-time63%

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