You Do Need power plug adapter while traveling from Bosnia & Herzegovina 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 Bosnia & Herzegovina are C and F. This is how they look like.

Bosnia & Herzegovina

In Bosnia & Herzegovina, outlets of type C and F are in use.

Type C

Type F

Cocos (Keeling) Islands

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

Type I