At age sixteen, Dittrich made her international debut at the 2006 European Junior Swimming Championships in Palma de Mallorca, Spain, where she captured two medals, silver and bronze, in the women's butterfly and individual medley (both 200 m), posting her time of 2:12.84 and 2:17.86, respectively.[4][5] In the same year, she won another bronze medal in the same discipline at the FINA Youth World Championships in Rio de Janeiro, Brazil, with a time of 2:13.92, four tenths of a second (0.40) behind runner-up Jemma Lowe of Great Britain.[6]
Dittrich qualified for the women's 200 m butterfly at the 2008 Summer Olympics in Beijing, by clearing a FINA B-cut of 2:10.86 from the International Vienna Championships in Vienna.[7] She challenged six other swimmers on the second heat, including South Africa's Katheryn Meaklim and Singapore's Tao Li. She came in second place, 0.44 of a second behind Meaklim, with an Austrian record-breaking time of 2:09.85. Dittrich, however, narrowly missed out of the semifinals by less than a second, as she placed seventeenth out of 36 swimmers in the preliminary heats.[8]
At the 2010 European Swimming Championships in Budapest, Hungary, Dittrich achieved a sixth-place finish in the women's 1500 m freestyle, posting a national record-breaking time of 16:23.63.[9]
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.[10] 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.[11] Shortly after the Olympics, Dittrich announced her retirement from swimming career.[3][12]