Oshima was born in Shizuoka on January 23, 1993. After graduating from Shizuoka Gakuen High School, he joined J1 League club Kawasaki Frontale in 2011. He played many matches as central midfielder from 2012. In 2017, Kawasaki won the J1 League champions first time in the club history. Kawasaki also won the J1 champions in 2018 and 2020.