You Do Need power plug adapter while traveling from Swaziland to Peru.

Here is Why You Need An Adapter

The outlet and plug type used in Peru are A, B and C and in Swaziland is M. This is how they look like.

Swaziland

In Swaziland, outlets of type M are in use.

Type M

Peru

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

Type A

Type B

Type C