You Do Need power plug adapter while traveling from Guinea 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 Guinea are C, F and K. This is how they look like.

Guinea

In Guinea, outlets of type C, F and K are in use.

Type C

Type F

Type K

Thailand

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

Type A

Type B

Type C

Type O