You Do Need power plug adapter while traveling from Congo 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 Congo are C, D and E. This is how they look like.

Congo

In Congo, outlets of type C, D and E are in use.

Type C

Type D

Type E

Thailand

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

Type A

Type B

Type C

Type O