The decision brings an end Du Plessis' 14-year association with IPL, where he represented Chennai Super Kings, Royal Challengers Bengaluru, Delhi Capitals and Rising Pune Supergiants while winning two titles.
The 41-year-old wrote in a statement on social media: "After 14 seasons in the IPL, I've decided not to put my name into the auction this year.
"It's a big decision, and one that comes with a lot of gratitude when I look back. "This league has been a massive part of my journey.
"I've been lucky to play with world-class teammates, for amazing franchises, and in front of fans whose passion is like nothing else. India has given me friendships, lessons, and memories that have shaped me as a cricketer and as a person."
Du Plessis is the fourth-highest run-scorer among overseas players in the IPL and did not rule out a return to the competition in the future.
He added: "Fourteen years is a long time, and I'm proud of what this chapter has meant to me. India has a special place in my heart, and this certainly isn't goodbye - you'll see me again.
"This year, I've chosen to take on a new challenge and will be playing in the upcoming PSL season.
"It's an exciting step for me - a chance to experience something new, to grow as a player, and to embrace a league filled with incredible talent and energy.
"A new country. A new environment. A new challenge. I'm looking forward to the Pakistan hospitality."
Du Plessis has played in the PSL before, making six appearances between 2019 and 2021 for Peshawar Zalmi and Quetta Gladiators.
Donovan Ferreira has been named as captain of Joburg Kings for the remainder of the SA20, replacing Faf du Du Plessis who has been ruled out after sustaining a right thumb ligament tear.
James Vince struck a fluent 75 to lead Joburg Super Kings to 187 for six, but persistent lightning forced the SA20 clash against Paarl Royals to be abandoned at the Wanderers, with the sides sharing the points.
Bangladesh has imposed an indefinite ban on the broadcast and promotion of the Indian Premier League following the controversial removal of fast bowler Mustafizur Rahman from Kolkata Knight Riders ahead of the 2026 season.
David Miller, Lungi Ngidi and Anrich Nortje were all bought for more than R3million at the Indian Premier League mini-auction, while Quinton de Kock also picked up a new deal.
