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

Here is Why You Need An Adapter

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

Liechtenstein

In Liechtenstein, outlets of type C and J are in use.

Type C

Type J

San Marino

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

Type C

Type F

Type L