Now 45, the seven-time Grand Slam singles champion will surpass Japan's Kimiko Date, who was 44 at the 2015 event. The 2026 Australian Open begins on January 18 and will mark Williams' first appearance at the season-opening major in five years.
Williams debuted at Melbourne Park in 1998, defeating her sister Serena before falling to Lindsay Davenport in the quarter-finals. She has since played the main draw 21 times, recording 54 wins and 21 losses, and finished runner-up to Serena in 2003 and 2017.
Her most recent appearance was in 2021, losing in the second round to Italy's Sara Errani. Since then, she has competed sparingly, mainly in the U.S., including the US Open last year, where she exited in the first round.
As part of her preparation, Williams will play lead-up events in Auckland and Hobart, starting January 12, alongside players like Emma Raducanu and Barbora Krejcikova.
"I'm excited to be back in Australia and looking forward to competing during the Australian summer," Williams said.
Off the court, she recently married Danish-born model and actor Andrea Preti in Florida and now prepares for a historic return to a venue central to her remarkable career.