You Do Need power plug adapter while traveling from Equatorial Guinea to Sint Maarten.

Here is Why You Need An Adapter

The outlet and plug type used in Sint Maarten are A and B and in Equatorial Guinea are C and E. This is how they look like.

Equatorial Guinea

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

Type C

Type E

Sint Maarten

In Sint Maarten, outlets of type A and B are in use.

Type A

Type B