You Do Need power plug adapter while traveling from Puerto Rico 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 Puerto Rico are A and B. This is how they look like.

Puerto Rico

In Puerto Rico, 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