You Do Need power plug adapter while traveling from South Korea 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 South Korea is F. This is how they look like.

South Korea

In South Korea, outlets of type F are in use.

Type F

San Marino

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

Type C

Type F

Type L