You Do Need power plug adapter while traveling from Iran 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 Iran are C and F. This is how they look like.

Iran

In Iran, outlets of type C and F are in use.

Type C

Type F

San Marino

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

Type C

Type F

Type L