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

Here is Why You Need An Adapter

The outlet and plug type used in South Korea is F 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

South Korea

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

Type F