You Do Need power plug adapter while traveling from Antigua and Barbuda to Pitcairn Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Pitcairn Islands is I and in Antigua and Barbuda are A and B. This is how they look like.

Antigua and Barbuda

In Antigua and Barbuda, outlets of type A and B are in use.

Type A

Type B

Pitcairn Islands

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

Type I