You Do Need power plug adapter while traveling from Rwanda to Cocos (Keeling) Islands.

Here is Why You Need An Adapter

The outlet and plug type used in Cocos (Keeling) Islands is I and in Rwanda are C, E, F and G. This is how they look like.

Rwanda

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

Type C

Type E

Type F

Type G

Cocos (Keeling) Islands

In Cocos (Keeling) Islands, outlets of type I are in use.

Type I