You Do Need power plug adapter while traveling from United States Virgin Islands to Christmas Island.

Here is Why You Need An Adapter

The outlet and plug type used in Christmas Island is I and in United States Virgin Islands are A and B. This is how they look like.

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

Type A

Type B

In Christmas Island, outlets of type I are in use.

Type I

I am from

going to