There are no hostels in Abbadia San Salvatore, but there are other types of accommodations...

THIS PROPERTY IS ABOUT 70 KM FROM SIENA.
Hotel Gambrinus, 3 STARS HOTEL , family run is located in panoramic position, with view on the Val d'Orcia and on the Mount Amiata, 1 km from the historic centre of Abbadia San Salvatore, an ancient medieval village situated at the foot of Mount Amiata.
A good point of departure to make excursions to Pienza, Montepulciano, Montalcino, or to the thermal Bath hot spring of Bagni San Filippo, only 7 kms away from the Hotel, Bagno Vignoni or Saturnia. ...