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

Here is Why You Need An Adapter

The outlet and plug type used in Marshall 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

Marshall Islands

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

Type A

Type B