In 2010, Yefimova won gold medals at the 2010 European Aquatics Championships in 50 m and 100 m breaststroke. In 2012, Yefimova received bronze in 200 m at the 2012 Summer Olympics, with 2:20.92. A year later at the 2013 World Aquatics Championships in Barcelona she triumphed in 200 m with 2:19.41. In the 50 m heats event, the Russian achieved a new world record of 29.78 which was broken in the semifinals by Rūta Meilutytė. Yefimova won the finals with 29.52.