Diario Gol says Bale has reached an agreement with Real Madrid to leave the Bernabeu next summer.
It's claimed Bale has already agreed terms with the club during a meeting between president Florentino Perez and the his agent Jonathan Barnett this week.
Both United and his former club Tottenham the front-runners to grab his signature.
Last week, Spurs boss Mauricio Pochettino stated: "He's always kept in contact with the people who worked here in the past.
"I don't have a close relationship with him or the people around him. But you never know what's going to happen in football."