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

Here is Why You Need An Adapter

The outlet and plug type used in Cayman Islands are A and B 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

Cayman Islands

In Cayman Islands, outlets of type A and B are in use.

Type A

Type B