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

Here is Why You Need An Adapter

The outlet and plug type used in Costa Rica are A and B 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

Costa Rica

In Costa Rica, outlets of type A and B are in use.

Type A

Type B