You Do Need power plug adapter while traveling from Cook Islands 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 Cook Islands is I. This is how they look like.

Cook Islands

In Cook Islands, outlets of type I are in use.

Type I

Cuba

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

Type A

Type B

Type C

Type L