[2] Kobayashi made her professional debut against Kira Matsutani at RISE Girls Power 2 on February 11, 2020.
She advanced to the finals of the one-day tournament, where she faced Koyuki Miyazaki.
[10] On November 2, 2022, Kobayashi made her debut in the -49kg division at RISE EVOL 11 against Wakana Miyazaki.
[11] Kobayashi rematched Koto Hiaroka in an open finger gloves bout at RISE 163 on December 10, 2022.
She won the fight by a unanimous decision after scoring a knockdown in the third round.
[15] Kobayashi faced Wang Chin Long at RISE 175 on January 14, 2024.