Japan participated in the 2018 Asian Games as a competing nation, in Jakarta and Palembang, Indonesia, from 18 August to 2 September 2018.

Nippon Badminton Association announced its squad of 20 players (10 men's and 10 women's) on 6 June 2018.

[4] The following is the Japan roster (Samurai team) for the men's baseball tournament of the 2018 Asian Games.

[10] Qualification legend: QF=Final; QS=Semifinal b Riders who entered the competition but did not participating in any phase of the team event.

[13] The following is the Japan roster in the men's field hockey tournament of the 2018 Asian Games.

[20] Head coach: Asako Takakura Japan men's and women's team were drawn in group B respectively.

[21] Key: All Japan Judo Federation delegate 14 judokas (7 men's and 7 women's) to compete at the Games.

[23] Japan rugby sevens men's and women's team entered the group B at the Games.

[24] The following is the Japan squad in the men's rugby sevens tournament of the 2018 Asian Games.