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

Peru

In Peru, outlets of type A, B and C are in use.

Type A

Type B

Type C

Saint Martin

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

Type C

Type E