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

Here is Why You Need An Adapter

The outlet and plug type used in Rwanda are C, E, F and G and in Swaziland is M. This is how they look like.

Swaziland

In Swaziland, outlets of type M are in use.

Type M

Rwanda

In Rwanda, outlets of type C, E, F and G are in use.

Type C

Type E

Type F

Type G