The 32-year-old goalie began his third spell at Iranian popular football team.
Rahmati joined Esteghlal in 2005 from Sepahan and left the team after two years for Mes Kerman.
He returned to Esteghlal in 2011 and was a member of the team until 2014.
Rahmati has penned a deal with Esteghlal for third spell for an undisclosed fee.