The former England captain who retired earlier this year after stints with Manchester United, Real Madrid and the MLS club LA Galaxy, had been considering several locations and toured Miami this summer, meeting with city and county leaders.
His MLS player contract included an option to create a new team for $25 million.
Beckham was still putting together a team of investors, the source said. The person spoke on condition of anonymity because Beckham's plans have yet to be officially announced.
His representatives are already looking at sites for a purpose-built soccer-only stadium, according to a well-placed source in Miami's business community.
"They have people looking real hard. They want to be in the urban core," the person said.
A fan group which has been campaigning for a team to come to the city welcomed the news. Julio Caballero, spokesman for the group, which calls itself MLS Miami Bid, posted "It's our time," on the group's Facebook page.
MLS confirmed it was in discussions with Beckham but declined to confirm if a deal had been struck.
"We are continuing our discussions with David Beckham regarding future ownership of an MLS expansion team," said Dan Courtemanche, a spokesman for MLS.
"Our policy regarding discussions with potential expansion team owners is that we keep those conversations private until the individuals we are speaking with decide they want to go public with their plans. Thus, it is more appropriate for David Beckham to comment on his plans."
Miami officials also reacted cautiously to the news. "We've not had any official notification that David Beckham has chosen Miami for a new Major League Soccer (MLS) franchise," Miami-Dade County Mayor Carlos Gimenez said.
"That said, I join the hundreds of thousands of soccer fans throughout South Florida who are ready and eagerly waiting for an MLS team to be established in Miami. A world-class community like Miami-Dade County, also known as the Gateway to the Americas, would be a fitting home for the world's most popular sport."
The greater Miami area has a large and growing Latin American population and local sports bars always draw large crowds during the World Cup every four years.
More than 70,000 fans attended an International Champions Cup match in Miami between Real Madrid and Chelsea in August.
The city briefly had an MLS team, the Miami Fusion, which played in neighbouring Fort Lauderdale. It joined MLS in 1998 but was closed by the then struggling league after four seasons.
The only professional team in the area is the Fort Lauderdale Strikers, which plays in the second-tier North American Football League.
When he was in Miami in June, Beckham visited two potential stadiums and declared Miami an "exciting" venue for a top-flight team.
Beckham visited Sun Life Stadium, home to the NFL's Miami Dolphins, whose owner Stephen Ross has expressed interest in investing in football events, and met with the Dolphins Chief Executive Mike Dee.
Sun Life can hold around 75,000 fans and has hosted several international friendlies in recent years but may be considered overly large for an MLS team.
Together with British entrepreneur Simon Fuller, whose management company 19 Entertainment handles Beckham's business affairs, Beckham later visited a 20,000-seat stadium at Florida International University.
Beckham was also accompanied by Bolivian-born billionaire Marcelo Claure, chief executive officer of Brightstar Corporation, a Miami-based wireless services company, who is also an avid football fan and owns one of Bolivia's top clubs, Bolivar.
Some sources have suggested Beckham might also be looking at the Miami Marlins baseball stadium as a temporary venue until a new football-only stadium is built.
- Sports & Recreation
- David Beckham
- Real Madrid