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

Here is Why You Need An Adapter

The outlet and plug type used in Ireland (Eire) is G and in Balearic Islands are C and F. This is how they look like.

Balearic Islands

In Balearic Islands, outlets of type C and F are in use.

Type C

Type F

Ireland (Eire)

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

Type G