Taneda competed for the Japanese team in a breaststroke double at the 2008 Summer Olympics in Beijing. Leading up to the Games, she emerged the only swimmer to meet the Olympic qualifying standard in the 100 m breaststroke with a 1:07.91, and then beat her rival Rie Kaneto to clear the FINA-A cut time in 2:24.54 for a 200 m breaststroke victory at the Olympic trials in Tokyo. On the second day of the Games, Taneda missed out the semifinals by 0.08 of a second, after finishing seventeenth in the preliminary heats of the 100 m breaststroke in 1:08.45. In her second event, 200 m breaststroke, Taneda rounded out the final in last place by nine hundredths of a second (0.09) behind her teammate Rie Kaneto in 2:25.23.