Yefimova's first notable achievement was winning the 50 m, 100 m and 200 m breaststroke titles at the 2007 European Short Course Swimming Championships. At the 2008 European Aquatics Championships she was the gold medalist in 200 m breaststroke and silver medalist in 50 m. She participated at the 2008 Summer Olympics in Beijing, reaching fourth place in 100 m and fifth place in 200 m breaststroke.