You Do Need power plug adapter while traveling from American Samoa to Cook Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Cook Islands is I and in American Samoa are A, B, F and I. This is how they look like.

American Samoa

In American Samoa, outlets of type A, B, F and I are in use.

Type A

Type B

Type F

Type I

Cook Islands

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

Type I