You Do Need power plug adapter while traveling from Costa Rica to Dominican Republic.

Here is Why You Need An Adapter

The outlet and plug type used in Dominican Republic are A, B and C and in Costa Rica are A and B. This is how they look like.

Costa Rica

In Costa Rica, outlets of type A and B are in use.

Type A

Type B

Dominican Republic

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

Type A

Type B

Type C