Natsumi Hoshi

is a Japanese competitive swimmer who specializes in the 200-meter butterfly. In this event she won the world title in 2015 and bronze medals at the 2012 and 2016 Olympics.

Hoshi studied sports science at Waseda University in Tokyo, and enjoys shopping in her spare time. In 2006, she showed symptoms of Graves' disease, a condition that results in an overactive thyroid and frequent fatigue. Her thyroid gland was removed in November 2014, and in January 2015 she returned to competitions. Earlier in 2011 she was named Best Athlete of the Year by the Saitama Swimming Federation.