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

Here is Why You Need An Adapter

The outlet and plug type used in Bonaire are A 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

Bonaire

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

Type A

Type C