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

Here is Why You Need An Adapter

The outlet and plug type used in Equatorial Guinea are C and E 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

Equatorial Guinea

In Equatorial Guinea, outlets of type C and E are in use.

Type C

Type E