You Do Need power plug adapter while traveling from British Virgin Islands to Sierra Leone.

Here is Why You Need An Adapter

The outlet and plug type used in Sierra Leone are D and G 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

Sierra Leone

In Sierra Leone, outlets of type D and G are in use.

Type D

Type G