You Do Need power plug adapter while traveling from Italy to Thailand.

Here is Why You Need An Adapter

The outlet and plug type used in Thailand are A, B, C and O and in Italy are C, F and L. This is how they look like.

Italy

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

Type C

Type F

Type L

Thailand

In Thailand, outlets of type A, B, C and O are in use.

Type A

Type B

Type C

Type O