To leave the BVI and go to the USVI and back, you must:
1 - clear out of the BVI
2 - Clear into the USVI [best option at Cruz Bay STJ ]
3 - Clear back into the BVI

In the BVI the Captain can do both the clearances alone with the vessel papers, everyone's passports and forms - In the USVI the whole crew must appear together at C&I - [those forms can be printed online.]