You Do Need power plug adapter while traveling from Azores 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 Azores are B, C and F. This is how they look like.

Azores

In Azores, outlets of type B, C and F are in use.

Type B

Type C

Type F

Cocos (Keeling) Islands

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

Type I