PHL - STL

$70 Find Cheap Flights from Philadelphia to St. Louis

This is the cheapest one-way flight price found by a KAYAK user in the last 72 hours by searching for a flight from Philadelphia to St. Louis departing on 5/10. Fares are subject to change and may not be available on all flights or dates of travel. Click the price to replicate the search for this deal.
1 adult
1 adult, Economy, 0 bags

KAYAK searches hundreds of travel sites at once for deals on flights to St. Louis

 
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Philadelphia to St. Louis, as well as popular online travel agencies
These are the airlines KAYAK users have selected most often from within our search results in flight searches from Philadelphia to St. Louis, as well as popular online travel agencies
Travelers love KAYAK
41.299.237 searches in the past 7 days on KAYAK

Save 24% or moreCompare multiple travel sites with one search.

Track pricesNot ready to book? Create a price alert for when prices drop.

Bundle and saveSave money when you bundle your flight + hotel.

Filter your dealsChoose cabin class, free Wi-Fi and more.

Everything you should know

Cheapest round-trip
$270
Typical prices: $606-$365
Frontier
Fri 5/8Sun 5/10
PHL - STL • 1 stop
Cheapest non-stop
$277
Typical prices: $648-$396
American Airlines
Wed 5/20Wed 5/27
PHL - STL • Non-stop
Advice from real travelers
AI-powered summary based on content written by travel experts. AI can make mistakes.
Southwest's two free checked bags suit heavy packers.
Use MetroLink for easy access from Lambert-St Louis.
Expert advice
Expert advice
Expert advice
Expert advice
Top airlines
Cheapest • from $270 (round-trip)
Best reviews • 8.0 score
Airline reviews
Airline reviews
+1
+1
Airline reviews
Airline reviews
+1
Nonstop flights
You can fly direct with American Airlines and Southwest. Average duration is 2h 34m
Direct flights
Direct flights
+1
+1
Direct flights
Direct flights
+1
Top layover airports
Cheapest • Avg $233 (round-trip)
Shortest trip • 4h 19m (one-way)
Insights
Insights
Insights
Insights
When to book
in advance
Our data shows that travelers who book at least 4 weeks in advance save around 49% compared to booking last minute.
Insights
Insights
Insights
Insights
When to travel
Cheapest • 23% price drop
Most popular
Good to know
Good to know
+1
+1
Good to know
Good to know
+1
Start a new search
KAYAK searches 100s of sites at once to find you the best travel deals.
We hope you love your trip to St. Louis!
Flight Deals
Booking Insights
Expert advice
Flight Deals

Cheap Flights from Philadelphia to St. Louis (PHL-STL)

 
Here are some of the best deals found on KAYAK recently from the most popular airlines for round-trip flights from Philadelphia to St. Louis that are departing in the next months. While these flights were available on KAYAK in the last 72 hours, prices and availability are subject to change and deals may expire.
Discover the best prices for you by selecting your travel dates on KAYAK.

Recent round-trip flight deals from Philadelphia to St. Louis

Fri, May 8 - Sun, May 10
Frontier Logo
5:04 pm - 12:21 am
PHL
-
STL
8h 17m
1 stop
Frontier Logo
8:08 pm - 5:37 am
STL
-
PHL
8h 29m
1 stop
$270Frontier
Wed, Jun 3 - Wed, Jul 1
Frontier Logo
8:35 pm - 7:23 pm
PHL
-
STL
23h 48m
1 stop
Frontier Logo
4:17 pm - 8:51 am
STL
-
PHL
15h 34m
1 stop
$271Frontier
Sat, May 16 - Mon, May 18
Multiple Airlines Logo
2:57 pm - 12:21 am
PHL
-
STL
10h 24m
1 stop
Multiple Airlines Logo
5:27 pm - 11:48 pm
STL
-
PHL
29h 21m
2 stops
$273Multiple Airlines
Thu, May 7 - Tue, May 12
Frontier Logo
5:37 am - 2:48 pm
PHL
-
STL
10h 11m
1 stop
Frontier Logo
6:33 pm - 1:06 pm
STL
-
PHL
17h 33m
1 stop
$274Frontier
Wed, May 20 - Wed, May 27
American Airlines Logo
11:06 am - 12:48 pm
PHL
-
STL
2h 42mnonstop
American Airlines Logo
6:15 am - 9:38 am
STL
-
PHL
2h 23mnonstop
$277American Airlines
Wed, May 13 - Fri, May 22
Frontier Logo
8:35 pm - 7:23 pm
PHL
-
STL
23h 48m
1 stop
Frontier Logo
5:27 pm - 4:38 pm
STL
-
PHL
22h 11m
2 stops
$278Frontier
Fri, May 1 - Sun, May 3
Frontier Logo
4:42 pm - 11:19 pm
PHL
-
STL
7h 37m
1 stop
Frontier Logo
8:06 pm - 5:34 am
STL
-
PHL
8h 28m
1 stop
$280Frontier
Tue, May 5 - Fri, May 8
Frontier Logo
9:20 am - 5:36 pm
PHL
-
STL
9h 16m
2 stops
Frontier Logo
5:27 pm - 1:06 pm
STL
-
PHL
18h 39m
1 stop
$282Frontier
Tue, Jun 16 - Sun, Jun 21
Frontier Logo
4:35 pm - 8:52 am
PHL
-
STL
17h 17m
1 stop
Frontier Logo
7:03 pm - 12:44 am
STL
-
PHL
52h 41m
2 stops
$283Frontier
Tue, May 5 - Wed, May 6
Frontier Logo
9:20 am - 5:36 pm
PHL
-
STL
9h 16m
2 stops
Frontier Logo
5:27 pm - 7:12 am
STL
-
PHL
12h 45m
1 stop
$285Frontier
Booking Insights

KAYAK's insights & trends for Philadelphia to St. Louis flights

Get data-powered insights and trends into flights from Philadelphia to St. Louis to help you find the cheapest flights, the best time to fly and much more.

How much is a round-trip flight from Philadelphia to St. Louis?

This analysis is based on the cheapest round-trip price found on KAYAK in the last 12 months by searching for a flight from Philadelphia to St. Louis departing in May.

What’s the cheapest day of the week to fly from Philadelphia to St. Louis?

The average price of all round-trip flights from Philadelphia to St. Louis clicked on KAYAK for each day over the last 12 months.

For Philadelphia to St. Louis, Wednesday is the cheapest day to fly on average and Monday is the most expensive. Flying from St. Louis back to Philadelphia, the best deals are generally found on Friday, with Saturday being the most expensive.

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

To calculate monthly average prices, KAYAK takes all prices for each month over the last year for round-trip flights from Philadelphia to St. Louis, removes the top 0.1% to account for outliers, and then takes the median of all values for each month.

The cheapest month for flights from Philadelphia to St. Louis is September, where tickets cost $314 (return) on average. On the other hand, the most expensive months are May and December, where the average cost of round-trip tickets is $484 and $467 respectively.

Can I save money by flying with a layover from Philadelphia to St. Louis?

The average round-trip price for all non-stop flights, flights with one layover, and flights with two layovers for the route found by users searching on KAYAK in the last 2 weeks.

Yes, flying with a layover may cost you more time, but you can also save money on the route, with a 1 stop layover the cheapest option at $421 on average.

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

To calculate weekly average prices, KAYAK takes all prices for each week before departure over the last year for round-trip flights from Philadelphia to St. Louis, removes the top 0.1% to account for outliers, and then takes the average of all the values for each week.

To get a below average price on the flight from Philadelphia to St. Louis, you should book around 4 weeks before departure, which saves you about 49% compared to booking last minute. For the absolute cheapest price, our data suggests you should book 17 weeks before departure.

Expert advice

Expert advice for your flight from Philadelphia to St. Louis

 
AI-powered summary based on content written by travel experts. AI can make mistakes.
KAYAK teamed up with top travel experts to share the best tips for your journey.
Our travel experts
Harriet Baskas

Harriet Baskas

Expert on American Airlines and PHL

Harriet is an award-winning journalist who is happiest in an airport or an unusual museum. Her stories about airports, air travel, and the business of travel have appeared on NBC News, CNBC, USA TODAY, The Points Guy and other outlets. She is the creator of the StuckatTheAirport.com blog and the author of nine books. When not out on the road or exploring the latest airport amenities, she’s home in Seattle getting ready for the next adventure.

Blane Bachelor

Blane Bachelor

Expert on Southwest

Blane Bachelor is a journalist and editor specializing in travel and aviation who writes regularly for top global outlets. Born and raised in Florida, Blane has worked and lived in four countries, including the Netherlands, where she’s currently based with her family. Her favorite way to get to know a new destination is by running or riding a bike around town – or hearing a spooky ghost story about local history. She will always choose the window seat.

Yulia Denisyuk

Yulia Denisyuk

Expert on STL

Yulia is a freelance journalist who’s dispatched from 90+ countries. Her work focuses on cultures, adventure trips and air travel, appearing in NatGeo, NYT, CNTraveler, and more. For past assignments, she’s stayed with nomads in Mongolia and learned the art of Imigongo in Rwanda. She’s based in Chicago; in winter she often questions that decision.

Good to know

Low seasonFebruary
Cheapest flight$70
Best time to beat the crowds but there is an average 6% increase in price.
Most popular time to fly with an average 18% increase in price.
Flight from Philadelphia to St. Louis

When to book flights from Philadelphia to St. Louis

Are your dates flexible? Find out the best times to travel from Philadelphia to St. Louis based on our flight data from the last year. Discover the cheapest month and even day to fly.
Estimated round-trip price
KAYAK looks at all historical flight data for each date to provide a predicted price for one-way trips or round-trips with a duration up to 40 days. While we try to provide actual minimum prices for each date, some prices are predictions and actual prices may differ.

FAQs for booking flights from Philadelphia to St. Louis

  • What is the cheapest flight from Philadelphia to St. Louis?

    In the last 3 days, the lowest price for a flight from Philadelphia to St. Louis was $70 for a one-way ticket and $270 for a round-trip.

  • Do I need a passport to fly between Philadelphia and St. Louis?

    No, a passport isn't needed to fly from Philadelphia to St. Louis. However, local authorities might ask for an official ID.

  • Which airports will I be using when flying from Philadelphia to St. Louis?

    Philadelphia and St. Louis are both served by 1 main airport. You will leave Philadelphia from Philadelphia and will be arriving at Lambert-St Louis.

  • Which airlines offer Wi-Fi service onboard planes from Philadelphia to St. Louis?

    American Airlines, JetBlue, Alaska Airlines, and Delta offer inflight Wi-Fi service on the Philadelphia to St. Louis flight route.

  • Which aircraft models fly most regularly from Philadelphia to St. Louis?

    The Airbus A319 is the aircraft model that flies most regularly on the Philadelphia to St. Louis flight route.

  • Which airline alliances offer flights from Philadelphia to St. Louis?

    SkyTeam, and oneworld are the airline alliances operating flights between Philadelphia and St. Louis, with SkyTeam being the most commonly used for this route.

  • On which days can I fly direct from Philadelphia to St. Louis?

    There are nonstop flights from Philadelphia to St. Louis on a daily basis.

  • Which is the best airline for flights from Philadelphia to St. Louis, Southwest or Delta?

    The two airlines most popular with KAYAK users for flights from Philadelphia to St. Louis are Southwest and Delta. With an average price for the route of $436 and an overall rating of 8.0, Southwest is the most popular choice. Delta is also a great choice for the route, with an average price of $442 and an overall rating of 7.9.

  • How does KAYAK find such low prices on flights from Philadelphia to St. Louis?

    KAYAK is a travel search engine. That means we look across the web to find the best prices we can find for our users. With over 2 billion flight queries processed yearly, we are able to display a variety of prices and options on flights from Philadelphia to St. Louis.

  • How does KAYAK's flight Price Forecast tool help me choose the right time to buy my flight ticket from Philadelphia to St. Louis?

    KAYAK’s flight Price Forecast tool uses historical data to determine whether the price for a flight to St. Louis from Philadelphia is likely to change within 7 days, so travelers know whether to wait or book now.

  • What is the Hacker Fare option on flights from Philadelphia to St. Louis?

    Hacker Fares allow you to combine one-way tickets in order to save you money over a traditional round-trip ticket. You could then fly to St. Louis with an airline and back to Philadelphia with another airline. Booking your flights between Philadelphia and STL can sometimes prove cheaper using this method.

  • What is KAYAK's "flexible dates" feature and why should I care when looking for a flight from Philadelphia to St. Louis?

    Sometimes travel dates aren't set in stone. If your preferred travel dates have some wiggle room, flexible dates will show you all the options when flying to St. Louis from Philadelphia up to 3 days before/after your preferred dates. You can then pick the flights that suit you best.

KAYAK’s top tips for finding a cheap flight from Philadelphia to St. Louis

  • Looking for a cheap flight? 25% of our users found flights on this route for $212 or less one-way and $362 or less round-trip.

Prefer to fly direct from Philadelphia to St. Louis?

 
Direct data is based off flight results for the next 60 days. Find direct flights from all airlines flying direct from Philadelphia to Lambert-St Louis.
Find which airlines fly direct from Philadelphia Airport to Lambert-St Louis Airport, which days they fly and book direct flights.

Direct departures

Philadelphia to Lambert-St Louis

Monday

American Airlines,Southwest

American Airlines,Southwest

Tuesday

American Airlines,Southwest

American Airlines,Southwest

Wednesday

American Airlines,Southwest

American Airlines,Southwest

Thursday

American Airlines,Southwest

American Airlines,Southwest

Friday

American Airlines,Southwest

American Airlines,Southwest

Saturday

American Airlines,Southwest

American Airlines,Southwest

Sunday

American Airlines,Southwest

American Airlines,Southwest

See more direct flights

Direct returns

Lambert-St Louis to Philadelphia

Monday

American Airlines,Southwest

American Airlines,Southwest

Tuesday

American Airlines,Southwest

American Airlines,Southwest

Wednesday

American Airlines,Southwest

American Airlines,Southwest

Thursday

American Airlines,Southwest

American Airlines,Southwest

Friday

American Airlines,Southwest

American Airlines,Southwest

Saturday

American Airlines,Southwest

American Airlines,Southwest

Sunday

American Airlines,Southwest

American Airlines,Southwest

See more direct flights

Reviews of the top 5 airlines serving from Philadelphia to St. Louis

 
See real verified KAYAK customer reviews for airlines flying from Philadelphia to St. Louis. Airline scores are aggregated from all reviews left by passengers on KAYAK after flying with an airline. KAYAK doesn’t show reviews that are older than 5 years. Learn how KAYAK collects reviews.
Need help choosing which airline to fly with from Philadelphia to St. Louis? KAYAK airline reviews give an overall score for each airline based on loads of factors, including comfort, boarding, in-flight entertainment and more, to make your decision easier. See airline scores according to verified KAYAK customer reviews.
8.0
SouthwestOverall score based on 4331 reviews
8.1Boarding
7.0Food
7.5Entertainment
8.6Crew
8.0Comfort
Airline reviews

The new boarding process was easy and straightforward. Very pleasant.

10.0 ExcellentAnonymous, Apr 2026
LAS - OKC
Read more Southwest reviews

The new boarding process was easy and straightforward. Very pleasant.

The flight was okay. The pilots did an amazing job and kept us updated on the flight. The flight attendants were okay. They found time to be chatty with each other rather than focus on the guests. One of the attendants was a little less warm when asking about my bag I had on my lap that I was using during latter part of the mid- flight. Mind you, it was not the departure descent. I’m respectful to each and every attendant, it was the tone in her voice reminding me to place my carryon bag on the floor. I hope to have a better experience next time.

The entire travel day was a disaster from beginning to end. Woke up at two in the morning to make it to San Juan airport in time for a 5:30 am flight to Milwaukee which connected in Baltimore. Massive delays lead to me missing original connection out of Baltimore. Sixteen hours of delays/rebooking/layover time later, arrived in Milwaukee to find that only one of two checked bags made it there (despite the fact that Southwest brought another 737 jet to San Juan to fly us out to our original Baltimore connection—-not squeezed into another booked flight). The flight from Baltimore to Milwaukee was barely half full, so there was no logical reason to ship my bags out of Baltimore on a different flight to Chicago to then ship to Milwaukee. Southwest decided that my bags should not have been on the same connecting flight I WAS ON to Milwaukee, and then proceeded to accidentally leave my larger bag with the important items in Chicago. Terrible logic and support all around. Extremely angered and disappointed with SW. What a clownish operation your company has become!

It was as expected and I was grateful for the wheel chair help and ease of use.

One of the best airlines for fast boarding, on time arrivals, and top notch service!

The new seat assignment thing is wierd. If you don’t pay for a seat they always assign you a middle seat regardless of how many people are on the flight. Idk… the new company that bought Southwest is trying to make it more profitable, but I’m just not seeing it. The flight attendants aren’t having as much fun anymore. It just feels like the airline is slowly dying. IMO. We shall see if Southwest is the next Toy’s R Us.

Terrible. Even though there’s assigned seating now, they are still the slowest boarding airline of anyone.

The Air hostess were very rude on my flight from Houston to Austin . Their regular communication itself felt a they are shouting at people.

Communication about the delayed flight was poor. We were told to move gates three times but that was bad information. We went from gate 128 to gate 126 and then to gate 123 and back to gate 126. Communication about the delay was bad. Ended up being 1 1/2 hour late getting home.

Plane was late. Zero service for 2+ hour flight and it was not that bumpy.

The tray table was broken and the food was terrible.

The gentleman at the gate I think his name is RIE was exceptional

While they turned off most cabin lights to allow people to sleep, I was bothered by how bright the side lights still were. It was still quite bright for me in a window seat, when I wish I could have slept!

One of the flight attendants was a little cranky. I appreciated the free wifi and plug to charge my laptop

No entertainment. Plane was so small had to pink tag a carry on ive used for 20 years easily on board. The fact the flight got in at midnight, had to wait for crew in fort wayne to allow the plane to approach the gate, THEN had to wait for bag on jet bridge made experience irritating at best.

Crew was great. Near on time departure and early arrival. Snacks are always meh. Not a fan of the "pay for everything including miles " proposal unless base flight rate going to be 100 bucks.

Would have been better if there was a nonstop flight from Tampa to Norfolk or Tampa to New Port News.

Overall Good! The weather delayed our takeoff from Atlanta and our arrival in Miami! If Mother Nature can mess up a flight she will do it every time!

The flight was smooth, the crew was great but the plane was quite old

Everything was great until I lost my water bottle and they can’t seem to locate it. I know I left it on the plane though.

Plane was super cold. No entertainment unless you were with mileage program Getting off the plane was super slow

We called Kayak for a change due to the TSA situation in Atlanta. What we got was a canceled return flight (in error) and we had to find the mistake. Not happy with Kayak who blamed it on AA.

I appreciate that I finally got the seat I paid extra for this time. Thank you

Half of the TSA checkpoints at PHL are closed. Also, there is no standby for first class passengers. You can only standby for coach. Very dated policy and inconsistent with peers.

It would have been nice if American tried to care.

Delayed initially because they couldn’t print the flight details. Poor instruction on delay. When I got on the plane the flight attendant argued with me about whether my carry on would fit (it did, although she didn’t acknowledge that). No greeting (other than arguing with me) getting on or off the plane.

Small plane, poor meal choices for first class, bad terminal and boarding experience at LAX

Boarding delayed 20 minutes for no reason, no wifi, in flight entertainment, or snacks / waters?

Beverage service was not good. Also just one service in 5 hr 30 min flight. No ask fir water ir anything beside one time beverage service.

They are always late and seats was also not having working charger

Horrible company: canceled flights and delayed flights. Spirit canceled my flight from Miami to Philadelphia the day before we were supposed to leave from Philadelphia to Miami, with no explanation. I had to rebook another flight, spending more money and instead of flying from Miami, I had to choose a flight from Fort Lauderdale because there were no direct flights available from Miami. That created additional cost. The flight with Spirit from Fort Lauderdale was scheduled to depart at 6am, so I had to wake up my 3 and 6 years old at 3am to get to the airport in time and then, at 5am while we were at the gate the delayed the flight until 7:45am with again no explanation.

Spirit is awful, and cost me an extra $400. On the flight to the destination they staff was rude and did not even offer water during the flight. On the return flight, while on the way to the terminal, Spirit cancelled the flight. This is the second time this has happened, and I believe they should compensate for the additional cost for incurred for the return flight. Spirit simply offered reimbursement for their cancelled flight, and did not take into consideration the cost for a last-minute flight home. The TSA agents expressed how Spirit often cancels evening/night flights, and shows no concern for the passengers.

The repeated flight delays—this time nearly three hours without any weather-related cause—are unacceptable. Yet, passengers are penalized heavily even for being a minute late. It is unreasonable that there is no compensation for such significant delays, nor even basic provisions like water during the wait or in flight. This imbalance in accountability is deeply frustrating and needs to be addressed.

My flight with spirit airlines was canceled leaving me stranded until tomorrow.

My flight was delayed then put back on time then cancelled and they automatically rebooked me to another flight but that flight was going to make me late to a concert i had planned for. Flight was at 10am concert was at 7pm from Burbank to Las Vegas so I allowed enough time but the flight that was rebooked was too late so I talked with the desk and they were able to get me on an afternoon flight. Thank goodness. That was stressful for a moment. I want to thank the person who helped me get to my show on time. Concert tickets are very expensive and the show was amazing. Hopefully my flight home will be smooth.

Unfortunately Stuff and the stuff boarded us were so rude to many of passengers.i will never fly Spirit again .

Always Good ,… Spirit customers are high class Delta customers are self proclaimed elites and American crews you can hear them complain about everything (they’re loud)

Very nice. Although, it would be nice to offer a glass of water for free. At least.....

They didn’t put my luggage on my transfer so I had to spend the night in Detroit. They said my luggage would be here in the morning and they’re still searching for it. It did not arrive apparently.

The attendant at the gate was not helpful at all and she was rude when we asked why the flight was delayed.

They switched our terminal 3 times and we were delayed for four plus hours!!!

It was an early flight and most people napped/slept and the crew let us which was nice.

The crew acted like they had never done this and kept barking passive aggressive orders at people. + the security line + the delay + sitting on the tarmac for 2 hours + none of the apps or signage updating with correct times

More inflight connection. And leg space is horrible. And the paying for baggage I'd ridiculous!!!

My flight was originally from SAT to MCO connecting from MCO to ORD. We got diverted to ATL and than Frontier staff there was sooo un helpful first they said they couldn’t give us any accommodation since our flight first got delayed that cancelled and now it’s 221am and I am still in ATL since they said they need to create a new flight my final destination is ORD and I have been delayed twice and cancelled. With no real help the frontier app didn’t work no email updates over all such a horrible experience

There's no seats that lean back with little leg space i wad uncomfortable the entire flight. Your charges for extra baggage is despicable and costly!!

Remind customers of the need to have passport or new ID for boarding.

Flight was canceled. Most upsetting was message from Kayak, stating that the flight was canceled and click with Kayak for details regarding rebook, refund details. THERE'S NO INFORMATION PROVIDED BY KAYAK EXCEPT THAT FLIGHT IS CANCELED. AND NOW THIS SURVEY TO FIND OUT HOW WAS THE FLIGHT !!!!!!!

The flight never took off and we spent 7 hours at the airport

Gate not determined until I got to the airport - hard to plan the trip to the airport.

Everything you need to know for your flight from Philadelphia to St. Louis

Other airlines flying from Philadelphia to St. Louis

Flights from the other most popular airlines that fly from Philadelphia to St. Louis according to KAYAK users. Prices are the lowest found on KAYAK over the last 7 days. Price and availability are not guaranteed.