Four years after competing in her first Olympics, Dittrich qualified for her second Austrian team, as a 22-year-old, at the 2012 Summer Olympics in London, by attaining a B-standard entry time of 8:39.67 in the women's 800 m freestyle. She challenged seven other swimmers on the second heat, including fellow two-time Olympians Khoo Cai Lin of Malaysia and Lynette Lim of Singapore. She came in fifth place, less than 0.03 of a second behind Mexico's Patricia Castañeda Miyamoto, with a time of 8:45.41. Dittrich, however, failed to advance into the final, as she placed twenty-eighth in the overall rankings. Shortly after the Olympics, Dittrich announced her retirement from swimming career.