You Do Need power plug adapter while traveling from Cocos (Keeling) Islands to South Africa.

Here is Why You Need An Adapter

The outlet and plug type used in South Africa are C, M and N and in Cocos (Keeling) Islands is I. This is how they look like.

Cocos (Keeling) Islands

In Cocos (Keeling) Islands, outlets of type I are in use.

Type I

South Africa

In South Africa, outlets of type C, M and N are in use.

Type C

Type M

Type N