Naomi Osaka has an older sister, Mari. Her sister was also a professional tennis player but retired in early 2021. Mari Osaka is 18 months older than Naomi and moved to the USA at the same time as her sister. The sisters played doubles together in the 2016 Toray Pan Pacific, just as Naomi was starting her rise in the game. When growing up, the competitive Naomi practiced hard to try and beat her older sister, which she finally did after 12 years.