Koki Yamaguchi outfielder (25) of the Lotte team posted photos showing him enjoying Disneyland with his family.

On the 17th, he updated his Instagram account with a post titled "Mickey Mouse." Yamaguchi held his eldest daughter and took a commemorative photo with Mickey Mouse along with his wife, former AKB48 and HKT48 member Aika Tada (31).

Yamaguchi played a key role in the final interleague game against DeNA on the 14th, hitting a go-ahead two-run single. He seemed to have enjoyed his brief off-season, adding the hashtag "#I'll do my best again starting tomorrow!"

Seeing the three of them wearing matching shirts, followers were touched and commented, "What a nice photo," "What a lovely holiday. Your children have grown so much! Your wife is cute too," and "Have a fun and refreshing holiday with your family and do your best in the second half of the year."

His wife, Tada, passed the 2006 AKB48 3rd generation additional member audition along with Yuki Kashiwagi and Mayu Watanabe. In 2012, she transferred to HKT48. She graduated in April 2017 to focus on acting. In November 2023, she announced her marriage to Lotte's Yamaguchi. Her husband, Yamaguchi, reported at a press conference after contract renewal negotiations that they had submitted their marriage registration in October of the same year. He revealed that he proposed to her on a cruise around Tokyo Bay. In October 2024, they announced the birth of their first child, a daughter.