"I have decided not to play in the South African league because I want to spend more time with my family," he said.
"We have the Asia Cup and World T20 Cup coming up early next year and before that I also wanted to take a break from the game."
Afridi is a popular player in the T20 format and recently in the series against Sri Lanka in the UAE, he became the first to make 1000 runs and take 50 wickets in the format.
Afridi is also being seen as a possible candidate to take over as the national T20 captain if the Pakistan Cricket Board decides to replace Muhammad Hafeez before the World T20.
PCB's acting chairman, Najam Sethi told reporters in Karachi the other day that there was pressure on Hafeez to retain his place in the national T20 team and the selectors would decide whether he should continue as captain.
Pakistan's Sohail Tanvir and off-spinner Saeed Ajmal have also signed up to play in the South Africa T20 league