Four years after competing in her first Olympics, Steinegger qualified for her second Austrian team, as a 29-year-old, at the 2012 Summer Olympics in London, by attaining an A-standard entry time of 4:41.33 in the 400 m individual medley. She challenged seven other swimmers on the fourth heat, including Great Britain's Hannah Miley, and defending Olympic champion Stephanie Rice of Australia. She came only in last place and twenty-third overall by 0.19 of a second behind Italy's Stefania Pirozzi, outside her Austrian record time of 4:45.80. In her second event, 200 m freestyle, Steinegger raced the second heat against seven other swimmers, including four-time Olympians Camelia Potec of Romania (former defending champion in 2004), and Hanna-Maria Seppälä of Finland (fourth-place finalist in the 100 m freestyle in 2008). She finished only in sixth place by 0.36 of a second behind Slovakia's Katarína Filová in 2:02.39. Steinegger, however, failed to advance into the semifinals, as she placed twenty-ninth out of 37 swimmers in the preliminary heats.