By train
To get to Ostia Lido by train, you need to take, once you arrive at Termini Station, the subway line "B" which will take you to Magliana Station. From there, you need to take the train to Ostia Lido and get off at the "Stella Polare" stop. From there, you can walk (about 200 meters) to the facility of your choice. The train ride from Rome to Ostia Lido should take about 30-40 minutes depending on intermediate stops and connections.