You Do Need power plug adapter while traveling from San Marino to Hong Kong.

Here is Why You Need An Adapter

The outlet and plug type used in Hong Kong is G and in San Marino are C, F and L. This is how they look like.

San Marino

In San Marino, outlets of type C, F and L are in use.

Type C

Type F

Type L

Hong Kong

In Hong Kong, outlets of type G are in use.

Type G