You Do Need power plug adapter while traveling from Vatican City 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 Vatican City are C, F and L. This is how they look like.

Vatican City

In Vatican City, outlets of type C, F and L are in use.

Type C

Type F

Type L

Saint Martin

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

Type C

Type E