You Do Need power plug adapter while traveling from South Africa to Cuba.

Here is Why You Need An Adapter

The outlet and plug type used in Cuba are A, B, C and L and in South Africa are C, M and N. This is how they look like.

South Africa

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

Type C

Type M

Type N

Cuba

In Cuba, outlets of type A, B, C and L are in use.

Type A

Type B

Type C

Type L