You Do Need power plug adapter while traveling from Costa Rica 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 Costa Rica are A and B. This is how they look like.

Costa Rica

In Costa Rica, outlets of type A and B are in use.

Type A

Type B

Åland Islands

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

Type C

Type F