Originally Posted by
Repooc17
PHL is close to the 30th St Amtrak station. From there take the train to Penn Station NY, then LIRR to Jamica and Airtrain to JFK.
But Amtrak will typically cost more than the bus.
OP: look for a bus that goes into Manhattan's Port Authority Bus Terminal, from which there is easy access to the Queens-bound "E" subway, which will take you to the JFK AirTrain station in Jamaica (subway stop "Sutphin/Archer/JFK").