The waterfront mansion is located on Palm Island, which is a man-made island on Biscayne Bay.
This latest purchase adds to his portfolio of expensive mansions, with the others located in Las Vegas and Beverly Hills.
Mayweather had previously owned a property in Miami Beach, on the La Gorce island, but this was put up for sale and sold in 2020.
His latest three-story mansion includes a 5,000-square-foot rooftop deck with views of the ocean and city skyline. It also comes with a gym, a movie theatre and games room.
Although it is not quite as big as his luxury $25.5million Beverly Hills residence, it does include nine bedrooms and four garages.
He officially took ownership of the property last week, after securing a deal through a Nevada-based entity named Fojoso LLC.
Mayweather, one of the most successful boxers of all time, recently came out of retirement to face YouTube sensation Logan Paul. The exhibition bout took place on June 6, with the fight going the full eight rounds and ending with no winner. It is said that the fight drew over 1 million buys on pay-per-view.
The 50-0 undefeated boxer had an incredible run during his boxing career, picking up victories against Manny Pacquiao, Canelo Alvarez and Oscar De La Hoya. His latest professional fight was against UFC star Conor McGregor, in which Mayweather won via technical knockout in round 10.
He has amassed an enormous amount of wealth through his high-profile bouts.
He is said to be officially retired from boxing, but is open to the idea of ‘making money’ with more potential exhibition matches in the future.
Mayweather, in 2019, topped the Forbes rich list of the decade with a staggering $706 million earned.