Two of the cases are foreign nationals, while a third is a person residing in Japan.
Since July 1, the organizing committee has recorded over 50 cases of the coronavirus among people related to the Games.
Over the weekend, several new cases of the coronavirus were reported among people residing in Olympic Village.
The 2021 Summer Olympics in Tokyo were initially scheduled for 2020 but were postponed in the spring of last year amid the coronavirus pandemic. The games are currently scheduled to be held from July 23 until August 8.