You Do Need power plug adapter while traveling from British Virgin Islands to Saint Barthélemy.

Here is Why You Need An Adapter

The outlet and plug type used in Saint Barthélemy are C and E and in British Virgin Islands are A and B. This is how they look like.

British Virgin Islands

In British Virgin Islands, outlets of type A and B are in use.

Type A

Type B

Saint Barthélemy

In Saint Barthélemy, outlets of type C and E are in use.

Type C

Type E