You Do Need power plug adapter while traveling from Réunion 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 Réunion are C and E. This is how they look like.

Réunion

In Réunion, outlets of type C and E are in use.

Type C

Type E

Antigua and Barbuda

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

Type A

Type B