You Do Need power plug adapter while traveling from São Tomé and Príncipe to Antigua and Barbuda.

Here is Why You Need An Adapter

The outlet and plug type used in Antigua and Barbuda are A and B and in São Tomé and Príncipe are C and F. This is how they look like.

São Tomé and Príncipe

In São Tomé and Príncipe, outlets of type C and F are in use.

Type C

Type F

Antigua and Barbuda

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

Type A

Type B