You Do Need power plug adapter while traveling from Sri Lanka 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 Sri Lanka is G. This is how they look like.

Sri Lanka

In Sri Lanka, outlets of type G are in use.

Type G

Åland Islands

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

Type C

Type F