You Do Need power plug adapter while traveling from San Marino to Sint Maarten.

Here is Why You Need An Adapter

The outlet and plug type used in Sint Maarten are A and B and in San Marino are C, F and L. This is how they look like.

San Marino

In San Marino, outlets of type C, F and L are in use.

Type C

Type F

Type L

Sint Maarten

In Sint Maarten, outlets of type A and B are in use.

Type A

Type B