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

Here is Why You Need An Adapter

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

Balearic Islands

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

Type C

Type F

Saint Martin

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

Type C

Type E