John is to play the stadium June 29. He will be supported by The Storys, a Swansea band, and former Coronation Street star Richard Fleeshman, the Western Mail said.
Stadium officials told the newspaper fewer than 1,000 tickets were still available for the show.
"It is going to be the biggest day in the short history of the Liberty, that much is guaranteed," Andrew Davies, general manager of the Swansea Stadium Management Co., told the Mail.
"The response has been incredible. To have sold almost 24,000 tickets for the concert with almost three whole months remaining is remarkable, and it means we will have a ... record crowd present when Sir Elton performs," Davies said. "To bring such a talented and world-renowned artist to the Liberty Stadium for his only Welsh performance this year is a major coup and we are delighted that the music fans of South-West Wales and beyond have recognized this."