You Do Need power plug adapter while traveling from Cayman 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 Cayman Islands are A and B. This is how they look like.

Cayman Islands

In Cayman Islands, outlets of type A and B are in use.

Type A

Type B

South Africa

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

Type C

Type M

Type N