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

Dominican Republic

In Dominican Republic, outlets of type A, B and C are in use.

Type A

Type B

Type C

Cocos (Keeling) Islands

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

Type I