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

Croatia

In Croatia, 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