[1] In June 2021, Sakai ended his six-year association with Oita Trinita and signed for the Thai League 1 club Samut Prakan City.

[3] On 2 September 2023, Indian Super League club Kerala Blasters announced the signing of Sakai.

[4] Sakai made his debut for the club on 21 September, in the season opener against Bengaluru at home, which the Blasters won 2–1.

[6] On 4 November, Sakai scored his debut goal for the Blasters during the match against East Bengal in the 32nd minute and helped them in 1–2 victory away from home.

[7] In October 2013, Sakai was elected Japan U-17 national team for 2013 U-17 World Cup.