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

Here is Why You Need An Adapter

The outlet and plug type used in Cuba are A, B, C and L and in Sint Maarten are A and B. This is how they look like.

Sint Maarten

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

Type A

Type B

Cuba

In Cuba, outlets of type A, B, C and L are in use.

Type A

Type B

Type C

Type L