You Do Need power plug adapter while traveling from Puerto Rico to Vatican City.

Here is Why You Need An Adapter

The outlet and plug type used in Vatican City are C, F and L 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

Vatican City

In Vatican City, outlets of type C, F and L are in use.

Type C

Type F

Type L