Koki Yamamoto (山本 幸輝, Yamamoto Kōki, born 29 October 1990 in Shiga Prefecture) is a Japanese rugby union player who plays as a prop.

[1] In his home country he plays for Yamaha Júbilo whom he joined in 2013.

[2][3] He was also named in the first ever Sunwolves squad which will compete in Super Rugby from the 2016 season.

[4]