[3] 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.

[7] She challenged six other swimmers on the second heat, including South Africa's Katheryn Meaklim and Singapore's Tao Li.

[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.

[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.