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

Here is Why You Need An Adapter

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

Cuba

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

Type A

Type B

Type C

Type L

Sint Eustatius

In Sint Eustatius, outlets of type A, B, C and F are in use.

Type A

Type B

Type C

Type F