Out of the infected athletes, two tested positive in the Olympic Village, the Japan Times reported on Sunday, citing officials.
Five Olympic Games staff members, a contract worker and a journalist also tested positive on Sunday.
The news comes after a South Korean member of the International Olympic Committee (IOC), Ryu Seung-min, tested positive for the virus after landing at Narita International Airport on Saturday.
The games, which were canceled last year due to the pandemic, will be held without spectators and under strict health protocols from July 23 to August 8.
The Japanese government has promised to do everything possible to ensure the safety of the athletes and the general public.
Opinion polls have consistently shown that the majority in Japan are in favor of postponing or canceling the games out of fears that such a major sporting event will lead to a wave of infections, and more contagious variants of the coronavirus.
Several protests were held on the matter.
International Olympic Committee (IOC) President Thomas Bach made an attempt to reassure the public in the final days leading up to the games:
“We are well aware of the skepticism a number of people have here in Japan. My appeal to the Japanese people is to welcome the athletes for their competitions,” he said on Saturday, adding that the IOC is interested in holding safe and secure events.
Bach insisted there was “zero” risk of the infected athletes passing the virus to other Olympic Village residents and the Japanese people.
In a similar vein, Olympic Games Executive Director Christophe Dubi said the risk of a new virus hotspot was extremely minimal.
“We can ensure that transmission between the various groups is almost impossible,” he said on Sunday.