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

Here is Why You Need An Adapter

The outlet and plug type used in Iceland are C and F and in United States Virgin Islands are A and B. This is how they look like.

United States Virgin Islands

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

Type A

Type B

Iceland

In Iceland, outlets of type C and F are in use.

Type C

Type F