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

Here is Why You Need An Adapter

The outlet and plug type used in Costa Rica are A and B 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

Costa Rica

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

Type A

Type B