On 13 July 2019, she made her international debut for Japan against Australia in their Australian tour.[1] She was still in her third year of High School when she earned her first cap.[1] She got her second cap in the last game of the two-test series, Australia won both games.[2]
In August 2022, Ireland toured Japan in a two-test series.[3] She scored a try in the first test despite her side being trounced 57–22.[3] She also featured in the second test which Japan won after defeating Ireland 29–10.[4][5] Imakugi was selected for Japan's squad to the delayed 2021 Rugby World Cup that was held in New Zealand.[6][7] She scored a try and kicked the conversion against the United States in their pool match, Japan lost 30–17.[1][8]
In April 2025, she played her 30th test against the United States at Wallis Annenberg Stadium in Los Angeles.[9] On 28 July, she was named in the Sakura's squad to the Women's Rugby World Cup in England.[10][11]