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St. Louis

$72+ Cheap flights from Pennsylvania 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 10/24. Fares are subject to change and may not be available on all flights or dates of travel.
PHL — STL
Aug 19 — Aug 261
Tue 8/19
Tue 8/26
1 adult, Economy
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Cheap flight deals from Pennsylvania to St. Louis

Keep the following information in mind while searching for Pennsylvania to St. Louis flight deals. Data was last updated August 14, 2025.

Round-trip from

$171
(American Airlines)

One-way from

$72
(CheapOair)

Popular in

May

Cheapest in

August

Average price

$316

Good round-trip deal

$235 or less

Good one-way deal

$142 or less
From Pennsylvania to Lambert-St Louis
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One-way flight from Pennsylvania to Lambert-St Louis
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Highest demand for flights based on searches. 7% potential increase in price ($31 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 Pennsylvania to Lambert-St Louis.
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Price to beat on a one-way flight from Pennsylvania to Lambert-St Louis.
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Find flight deals from Pennsylvania to St. Louis

Cheapest flights from Pennsylvania to St. Louis
Explore the most affordable flight options available from Pennsylvania to St. Louis. Find the lowest fares from popular airlines and budget airlines, with prices last updated on August 14, 2025.

This American Airlines deal was found by Cheapflights users on 8/12. 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.
Tue 10/75:06 pmPIT - STL
1 stop7h 48mAmerican Airlines
Thu 10/96:00 amSTL - PIT
1 stop7h 42mAmerican Airlines
Deal found 8/12$171
This American Airlines deal was found by Cheapflights users on 8/14. 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 American Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Thu 10/210:35 amPIT - STL
1 stop6h 11mAmerican Airlines
Mon 10/66:00 amSTL - PIT
1 stop7h 42mAmerican Airlines
Deal found 8/14$174
This Southwest deal was found by Cheapflights users on 8/11. 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 10/26:20 amPIT - STL
1 stop3h 30mSouthwest
Mon 10/68:15 amSTL - PIT
Nonstop1h 35mSouthwest
Deal found 8/11$177
This Priceline deal was found by Cheapflights users on 8/13. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/236:10 amIAD - STL
1 stop8h 23mFrontier
Mon 8/252:01 pmSTL - IAD
1 stop9h 15mFrontier
Deal found 8/13$180
This United Airlines deal was found by Cheapflights users on 8/14. 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 United Airlines is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 9/85:53 pmIAD - STL
1 stop6h 51mUnited Airlines
Wed 9/108:15 amSTL - IAD
Nonstop2h 10mUnited Airlines
Deal found 8/14$183
This Southwest deal was found by Cheapflights users on 8/13. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Wed 11/57:55 amPIT - STL
1 stop6h 10mSouthwest
Tue 11/186:15 pmSTL - PIT
Nonstop1h 35mSouthwest
Deal found 8/13$183
This Southwest deal was found by Cheapflights users on 8/14. 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 Southwest is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 11/106:00 amDCA - STL
1 stop5h 25mSouthwest
Sun 11/163:55 pmSTL - DCA
Nonstop1h 55mSouthwest
Deal found 8/14$183
This Mytrip deal was found by Cheapflights users on 8/14. 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 Mytrip is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 10/41:02 pmIAD - STL
1 stop21h 52mFrontier
Sun 10/1210:17 amSTL - IAD
1 stop21h 52mFrontier
Deal found 8/14$185
This Frontier deal was found by Cheapflights users on 8/14. 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.
Thu 9/116:10 amIAD - STL
1 stop9h 54mFrontier
Thu 9/1810:49 amSTL - IAD
2 stops12h 26mFrontier
Deal found 8/14$186
This Priceline deal was found by Cheapflights users on 8/13. 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 Priceline is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Mon 8/256:10 amIAD - STL
1 stop7h 46mFrontier
Mon 8/252:01 pmSTL - IAD
1 stop9h 15mFrontier
Deal found 8/13$187
This FlightHub deal was found by Cheapflights users on 8/14. 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 FlightHub is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Sat 8/236:10 amIAD - STL
1 stop8h 23mFrontier
Sun 8/2410:17 amSTL - IAD
1 stop22h 10mFrontier
Deal found 8/14$188
This Justfly.com deal was found by Cheapflights users on 8/13. 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 Justfly.com is selected, and click “Compare selected” under the list of providers to see comparable flight deals.
Fri 10/105:54 amEWR - STL
1 stop5h 43mMultiple Airlines
Tue 10/1410:57 amSTL - EWR
1 stop11h 34mMultiple Airlines
Deal found 8/13$188

Cheapflights Fare Finder

 
Customize your flight search to find flights from Pennsylvania 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 14, 2025.
Use the filters below to find and compare flights from Pennsylvania to St. Louis that are best for you.

Fly from

Pennsylvania

Fly to

St. Louis

Route

Depart

Return

Price

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Tue 10/7

7:17 am-1:44 pm

1 stop7h 27m

Lambert-St Louis

Thu 10/9

6:00 am-2:42 pm

1 stop7h 42m

$171

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Tue 10/28

7:35 am-1:44 pm

1 stop7h 09m

Lambert-St Louis

Tue 11/4

6:00 am-3:33 pm

1 stop8h 33m

$171

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Wed 11/5

12:21 pm-8:23 pm

1 stop9h 02m

Lambert-St Louis

Tue 11/18

6:00 am-3:33 pm

1 stop8h 33m

$171

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Tue 10/7

6:09 am-1:44 pm

1 stop8h 35m

Lambert-St Louis

Mon 10/13

7:16 am-4:34 pm

1 stop8h 18m

$171

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Wed 11/5

8:15 am-4:47 pm

1 stop9h 32m

Lambert-St Louis

Tue 11/11

6:00 am-4:35 pm

1 stop9h 35m

$171

PittsburghSt. Louis

PIT - STL

PITSTL

Pittsburgh

Fri 9/26

6:18 pm-11:07 pm

1 stop5h 49m

Lambert-St Louis

Mon 9/29

6:05 am-2:44 pm

1 stop7h 39m

$174

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Sat 8/23

6:10 am-1:33 pm

1 stop8h 23m

Lambert-St Louis

Mon 8/25

2:01 pm-12:16 am

1 stop9h 15m

$180

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Tue 9/9

1:15 pm-6:23 pm

1 stop6h 08m

Lambert-St Louis

Wed 9/10

1:10 pm-4:20 pm

Nonstop2h 10m

$183

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Wed 9/10

8:40 am-10:02 am

Nonstop2h 22m

Lambert-St Louis

Wed 9/17

7:04 pm-12:32 am

1 stop4h 28m

$183

Washington, D.C.St. Louis

IAD - STL

IADSTL

Washington, D.C. Dulles Intl

Mon 9/8

5:53 pm-11:44 pm

1 stop6h 51m

Lambert-St Louis

Wed 9/10

8:15 am-11:25 am

Nonstop2h 10m

$183

Flights are sorted by cheapest round-trip flights first.

Deals found on 8/14

Showing 1-10 of 60 results
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Best time to book a flight from Pennsylvania to St. Louis

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

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

Currently, August is the cheapest month in which you can book a flight from Pennsylvania to St. Louis (average of $311). Flying from Pennsylvania 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 PA to STL?

Find hourly flight availability from Pennsylvania 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 14, 2025.

Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Pennsylvania to St. Louis as you normally would.

Weekly flight availability from Pennsylvania to St. Louis

Explore weekly flight availability from Pennsylvania 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 August 14, 2025.

The most flights from USPA to STL are scheduled on a Monday (9 on average). You will have fewer flight options on Saturday, which is when the least amount of flights are scheduled (2 on average).

Related info for your journey

Find useful and relevant information for your journey from Pennsylvania 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 Pennsylvania?

    Located just 12.7 mi from the city center, Lambert-St Louis (STL) is the airport most travelers will use when flying to St. Louis from Pennsylvania.

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

    Flights from Pennsylvania to Lambert-St Louis have been viewed 33 times in the past calendar month.

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

    For one-way options, check prices for Frontier. According to our data, you can fly for as low as $72. Users have also found prices from $87 and $109 on American Airlines and Delta, respectively.

  • What are the most popular routes from Pennsylvania to St. Louis?

    While some choose either New York LaGuardia - Lambert-St Louis or New York John F Kennedy Intl - Lambert-St Louis, Newark - Lambert-St Louis is the most popular route from Pennsylvania to St. Louis.

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

    Consider PSA Airlines (100%), American Airlines (75%) or Qatar Airways (73%) when booking your flight. These represent the most reliable airlines when flying from Pennsylvania to St. Louis.

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

    The cheapest flight price from Pennsylvania to St. Louis is $88. On average you can expect to pay $293. The most popular route, (Newark - Lambert-St Louis), can usually be booked for $188.

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

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

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

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

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

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

    Currently, August is the cheapest month in which you can book a flight from Pennsylvania to St. Louis (average of $311). Flying from Pennsylvania 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 Pennsylvania to St. Louis

See prices for flight routes from nearby airports that may be better suited for you.
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George Bush Intcntl to Kansas City flights
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Top 6 airlines flying from Pennsylvania to St. Louis

Discover the top 6 airlines that operate flights from Pennsylvania 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 14, 2025.
AirlineCheapestAverageFlexibilityOn-time
FrontierCheapest$75Average$220FlexibilityNo cancel feeOn-time62%
Spirit AirlinesCheapest$95Average$178FlexibilityNo cancel feeOn-time65%
American AirlinesCheapest$177Average$365FlexibilityNo cancel feeOn-time71%
United AirlinesCheapest$236Average$458FlexibilityNo cancel feeOn-time69%
DeltaCheapest$238Average$363FlexibilityNo cancel feeOn-timeN/A
SouthwestCheapest$244Average$378FlexibilityNo cancel feeOn-time63%

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