With worsening weather conditions throughout the day, it became evident that no play would take place.
This marks Mohammad Rizwan's second T20I series defeat as Pakistan's captain, the first being a 3-0 whitewash against Australia in November.
South Africa triumphed in both of the opening matches, held in Durban and Centurion.
In the first T20I, South Africa set a target of 183/9, with David Miller scoring 82 off 40 balls and George Linde contributing 48 off 24. Pakistan managed 172/8, despite Mohammad Rizwan’s 72 runs, and South Africa won by 11 runs.
In the second T20I, Pakistan posted 206/5, led by Saim Ayub’s unbeaten 98 off 57 balls. South Africa chased the target comfortably, with Reeza Hendricks smashing 117 off 63 balls and Rassie van der Dussen finishing on 66* to win by 7 wickets in 19.3 overs.
With the T20I series wrapped up, both teams now turn their attention to the ODI series, starting on December 17 at Boland Park, Paarl.
Pakistan Playing XI: Mohammad Rizwan (wk/c), Babar Azam, Saim Ayub, Salman Ali Agha, Tayyab Tahir, Irfan Khan, Shaheen Afridi, Abbas Afridi, Jahandad Khan, Haris Rauf, Abrar Ahmed