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

Here is Why You Need An Adapter

The outlet and plug type used in Cayman Islands are A and B 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

Cayman Islands

In Cayman Islands, outlets of type A and B are in use.

Type A

Type B