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

Equatorial Guinea

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

Type C

Type E

Cuba

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

Type A

Type B

Type C

Type L