'TBE' will take on the second Japanese fighter since retiring from professional boxing in Mikuru Asakura.
The pair will collide in September and Mayweather will announce a date and venue later this month under Japanese MMA RIZIN promotion.
Mayweather - who knocked out Tenshin Nasukawa in his first exhibition since retiring as a pro - is excited to continue fighting around the world.
"I got to where I got to by working extremely hard,' Mayweather said. 'I'm always focused. I'm always pushing to be the best.
"It's still a great feeling to travel the world, do these exhibition fights and entertain people from all walks of life. I've seen every style.
"My job is just to go out there, have fun and be my best. September we're going to have fun and entertain people. I'm Floyd Mayweather to him. He's just another opponent to me."
Asakura, 29, has no boxing pedigree although he has an MMA record of 16-3.
He said: "I'm an MMA fighter but I'm going to use this opportunity and I'm going to use him to raise my name and my value internationally. I will win this fight."
Nobuyuki Sakakibara, CEO of Rizin, added: "I'm very happy to be sitting in between these two athletes for this event which will be Floyd Mayweather's second with RIZIN.
"Floyd Mayweather was supposed to fight in an exhibition in Japan earlier in the year with an organization called Mega.
"However, due to the pandemic it has been postponed and RIZIN has taken over the contract for Floyd Mayweather's next fight in Japan."
Mayweather is fighting for the second time this year after taking on former sparring partner Don Moore in the UAE. He has also fought YouTuber Logan Paul.
The announcement is a blow to Manny Pacquiao after his manager told Planet Sport that he wanted a rematch against Mayweather this year.