The veteran striker's much-anticipated arrival will give him good time to prepare for his side's A-League opener, much to the pleasure of his new coach
The former Italy star signed a two-year deal with the Sky Blues on September 5, a month before the start of the 2012-13 A-League season.
And Del Piero, 37, is giving himself every chance of making a bright start to his new career with his earlier-than-expected arrival.
Sydney coach Ian Crook said Del Piero's decision to arrive on Sunday highlighted his professionalism.
"It's fantastic news that he is arriving on Sunday and we look forward to integrating him into the Sydney FC team," Crook said via a statement.
"He is coming out a little bit earlier than we had thought, which is good and shows he's a pro and is keen to get started, which we knew was the case.
"As a coaching and medical group we'll have a chat to him and a good look at him so we can plan through that process."
Del Piero has reportedly been training in Turin for the past few months and is expected to arrive in decent shape.
Sydney chief executive Tony Pignata, who flew to Italy to help complete the signing, said Del Piero was keen to get started.
"It's exciting that we have an arrival date for Alessandro to arrive in Sydney to start his Sydney FC career," he said.
"He arrives on Sunday morning. He is eager to get here and start working with the team.
"There has been a lot of excitement surrounding his signature and we can now look forward to him joining the rest of the squad."
Del Piero rejected several offers from European-based clubs, reportedly including English Premier League giants Liverpool, to sign for Sydney for a reported €1.6 million [£1.3m] per season.
The 91-cap Italy international could make his debut for Sydney in their final pre-season match against Newcastle on September 22.
His first competitive appearance is likely to be in New Zealand, where the Sky Blues take on the Wellington Phoenix on October 6.
Meanwhile, a report in The Sydney Morning Herald suggests new A-League club and Sky Blues' city rivals Western Sydney Wanderers were also interested in signing Del Piero if the deal with Sydney fell through.