You Do Need power plug adapter while traveling from Solomon Islands to Balearic Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Balearic Islands are C and F and in Solomon Islands are G and I. This is how they look like.

Solomon Islands

In Solomon Islands, outlets of type G and I are in use.

Type G

Type I

Balearic Islands

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

Type C

Type F