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

Here is Why You Need An Adapter

The outlet and plug type used in Åland 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

Åland Islands

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

Type C

Type F