You Do Need power plug adapter while traveling from American Samoa to Great Britain.

Here is Why You Need An Adapter

The outlet and plug type used in Great Britain is G 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

Great Britain

In Great Britain, outlets of type G are in use.

Type G