You Do Need power plug adapter while traveling from Western Sahara 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 Western Sahara are C and E. This is how they look like.

Western Sahara

In Western Sahara, outlets of type C and E are in use.

Type C

Type E

Costa Rica

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

Type A

Type B