You Do Need power plug adapter while traveling from Belize to Ireland (Eire).

Here is Why You Need An Adapter

The outlet and plug type used in Ireland (Eire) is G and in Belize are A, B and G. This is how they look like.

Belize

In Belize, outlets of type A, B and G are in use.

Type A

Type B

Type G

Ireland (Eire)

In Ireland (Eire), outlets of type G are in use.

Type G