MLS is welcoming two new teams for the 2020 season, with Inter and Nashville SC taking the league to 26 franchises.
The full schedule for the next campaign is still to be confirmed, with the 2019 season only ending on Sunday as Seattle Sounders defeated Toronto FC in the MLS Cup final.
But Inter have announced their first official home fixture, with Beckham's team to come up against Galaxy at their temporary stadium in Fort Lauderdale on March 14.
Galaxy have a statue of Beckham outside their own stadium in southern California.
The former England captain made 98 regular season appearances for the club, scoring 40 times, and won the MLS Cup twice, in 2011 and 2012, and the Supporters' Shield twice, in 2010 and 2011.
MLS announced in 2014 that Beckham had exercised his option for an expansion franchise – built into his Galaxy contract – resulting in his involvement with Miami.
Inter have been linked with former Barcelona and Liverpool midfielder Javier Mascherano, who is currently at Hebei China Fortune, as they build their first squad.