On June 1, 2012, Kamamoto underwent surgery for a broken left hand.[4]
In 2012 - 2015 season, he played in informal matches against Shikoku Island League Plus's teams and amateur baseball teams, and played in the Western League of NPB's minor leagues.
In 2017 season, Kamamoto played two games in the Pacific League. And he recorded a 26 stolen bases in the Western League and was honored with the 2017 Western League Most Stolen base Leader Award and 2017 Western League Excellent Player Award.[8]
In 2018 season, Kamamoto played 6 games in the Pacific League.
On April 6, 2019, Kamamoto recorded his first hit against Chiba Lotte Marines.[9] On the 7th of the following day, he recorded his first home run.[10]
In the 2019 season, he finished the regular season in 86 games with a batting average of .270, a 4 home runs, a 11 stolen bases.
In 2020 season, Kamamoto finished the regular season in 32 games with a batting average of .192, and a RBI of 2. And he was selected as the Japan Series roster in the 2020 Japan Series.[11]
In 2021 season, Kamamoto finished the regular season in 18 games with a batting average of .500, a RBI of 3. On October 26, the Hawks announced release him.[12]
In 2022 season, Kamamoto played in 96 games with a batted .259, one home run, and a 26 RBIs in the Eastern League, but the Eagles announced his release on October 19.[14][15]
After retirement
On January 20, 2023, Kamamoto announced his retirement from active player. He has been a team staff member for the Fukuoka SoftBank Hawks since the 2023 season.[16]
On October 31, 2023, kamamoto became the fourth squad outfield defense and base running coach of the Fukuoka Softbank Hawks.[1]
^In the NPB, in addition to the 70 registered players under control (active roster of players), each team can have developmental players for the purpose of improving their baseball skills and training manners. They aim to be promoted to registered players under control within the 3 year contract period (Non-tender FA players and contract expired players renew their contract every year).