You Do Need power plug adapter while traveling from Gambia 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 Gambia is G. This is how they look like.

Gambia

In Gambia, outlets of type G are in use.

Type G

San Marino

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

Type C

Type F

Type L