Eri Yamanoi

is a former freestyle swimmer from Japan, who competed for her native country at the 1996 Summer Olympics in Atlanta, United States. There she finished in fourth place in the 4 × 200 m freestyle relay, alongside Aiko Miyake, Naoko Imoto, and Suzu Chiba.

On her individual starts, in the 400m freestyle, she ended up in 7th place, clocking 4:11.68 in the final; and in tenth place in the 800m freestyle with a time of 8:40.47 (preliminary heats). A year later, Yamanoi won the gold medal in the 400 free at the Summer Universiade. In 1998, she finished third in the 800m freestyle at the Asian Games in Bangkok, Thailand.

She is a graduate of Ina Junior High School in Tsukubamirai, Ibaraki, known locally for its Olympic-size swimming pool.