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

Here is Why You Need An Adapter

The outlet and plug type used in Saint Barthélemy are C and E and in Åland Islands are C and F. This is how they look like.

Åland Islands

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

Type C

Type F

Saint Barthélemy

In Saint Barthélemy, outlets of type C and E are in use.

Type C

Type E