You Do Need power plug adapter while traveling from Switzerland 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 Switzerland are C and J. This is how they look like.

Switzerland

In Switzerland, outlets of type C and J are in use.

Type C

Type J

Cocos (Keeling) Islands

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

Type I