You Do Need power plug adapter while traveling from Marshall Islands to South Sudan.

Here is Why You Need An Adapter

The outlet and plug type used in South Sudan are C and D and in Marshall Islands are A and B. This is how they look like.

Marshall Islands

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

Type A

Type B

South Sudan

In South Sudan, outlets of type C and D are in use.

Type C

Type D