From Madrid, train connections reach Alhama de Aragón. Take a taxi from there to the monastery.
From Zaragoza, head southwest on the N-II through Calatayud. At the little town of Ateca, take the left turnoff, which is marked for Nuévalos and the Monasterio de Piedra, and drive for 23km (14 miles). If you're driving from Madrid, take the N-II and turn east at the spa town of Alhama de Aragón.