"Born in
Oita, Mitoma grew up in the
Kawasaki area and joined the Frontale academy at the U10 level. Offered a promotion from the U-18s to the senior team coached by
Yahiro Kazama, he chose instead to matriculate to
University of Tsukuba, a Japanese university football powerhouse who had recently produced Frontale stalwarts such as
Shogo Taniguchi and
Shintaro Kurumaya. Mitoma professed to feel unprepared to enter professional football at age 18, citing the struggles of fellow Kawasaki academy products
Ko Itakura and
Koji Miyoshi to win regular playing time with the senior squad.
[3]"
18 yasinda kendisini profesyonel futbolcu olmaya hazir görmemis diye, üniversiteye gitmeyi tercih etmis.