You Do Need power plug adapter while traveling from Cape Verde to Equatorial Guinea.

Here is Why You Need An Adapter

The outlet and plug type used in Equatorial Guinea are C and E and in Cape Verde are C and F. This is how they look like.

Cape Verde

In Cape Verde, outlets of type C and F are in use.

Type C

Type F

Equatorial Guinea

In Equatorial Guinea, outlets of type C and E are in use.

Type C

Type E