You Do Need power plug adapter while traveling from Trinidad & Tobago to São Tomé and Príncipe.

Here is Why You Need An Adapter

The outlet and plug type used in São Tomé and Príncipe are C and F and in Trinidad & Tobago are A and B. This is how they look like.

Trinidad & Tobago

In Trinidad & Tobago, outlets of type A and B are in use.

Type A

Type B

São Tomé and Príncipe

In São Tomé and Príncipe, outlets of type C and F are in use.

Type C

Type F