PHL to STL, Philadelphia International Airport to St. Louis Lambert International Airport Cheap Flights

Based on HopeGoo data, Frontier Airlines offers one-way fares as low as US$110 on Cheapest nonstop routes (e.g. PHL to STL on Sun, Mar 1), while Frontier Airlines offers Cheapest nonstop round-trips from US$312 departing on Sun, Mar 8 and returning on Thu, Mar 12.

At the moment, you can catch a nonstop flight from Philadelphia to St. Louis with the following airlines, including: American Airlines Selected airlines are based on historical data collected from flight bookings users made on HopeGoo within the last 90 days.

It takes about 2 hours 38 minutes to fly from Philadelphia to St. Louis.

By analyzing data from all airlines on the HopeGoo flight calendar, it looks like the best time to book a flight from Philadelphia to St. Louis is around 40 days (6 weeks) in advance, and the best time to fly is usually on Tuesday, Wednesday, and Saturday. Tuesday typically offers the cheapest flights for departure, while Saturday offers the best return deals.

Based on HopeGoo data in the past 4 weeks, there is 9 flight per week flying from Philadelphia to St. Louis. You can check the weekly schedule for popular airlines on this route below: American Airlines: S/M/T/W/T/F/S -- AA3162 (11:07)

To find best deals on flights from Philadelphia to St. Louis, you can use various tools on HopeGoo: · Be flexible with your travel dates to get the cheapest flight deal. Now the cheapest flight deal is on Sun, Mar 1, with one-way flights priced at just US$110. · Compare airlines strategically. Budget carriers often provide the lowest base fares, while we found the most affordable airline currently operating on this route is American Airlines. · Set up price alerts to easily monitor ticket prices without having to check every day. · Check HopeGoo flight deals and promo codes frequently. · Avoid peak season unless you book very early. It seems the peak season for St. Louis travel is around January. · Get exclusive promo codes for HopeGoo app users.

The cheapest months to fly from Philadelphia to St. Louis is October, when demand for travel is lower.

After crunching the numbers on our February flight calendar, it's currently cheapest to fly from Philadelphia to St. Louis on February 28, 2026 with Frontier Airlines, with prices starting at US$193.

You can land at any one of the following hubs in St. Louis, with Philadelphia International Airport to St. Louis Lambert International Airport (PHL-STL) is by far the most common option on this route: St. Louis Downtown Airport (CPS) St. Louis Lambert International Airport (STL).

The time difference between St. Louis and Philadelphia is 1h.

Tickets can only be changed or canceled if permitted by airline policy. To submit a change or cancellation request, go to the flight bookings page, select the option to change or cancel your HopeGoo, choose the relevant passengers and segment, and submit a request. Please note that additional charges may apply according to the airline ticket policy. However, if the flight has been rescheduled and you would like to change or cancel your ticket, you can submit an involuntary cancellation request. For more details about change and cancellation policies, please check the customer support pages.