You Do Need power plug adapter while traveling from Gibraltar 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 Gibraltar is G. This is how they look like.

Gibraltar

In Gibraltar, outlets of type G are in use.

Type G

Sint Eustatius

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

Type A

Type B

Type C

Type F