Săpunaru began his senior career in 2002 with Național București, and went on to make a name for himself at Rapid București. In 2008, he signed with Porto in Portugal where he won ten major honours over the course of four years, including the 2011 Europa League. After two additional seasons in Spain playing for Zaragoza and Elche, Săpunaru spent his late years with stints in his native country and Turkey.