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

Here is Why You Need An Adapter

The outlet and plug type used in Mauritius are C and G 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

Mauritius

In Mauritius, outlets of type C and G are in use.

Type C

Type G