They are not offering testing at STT or at the ferry docks in USVI. I doubt they will as the current process has been working well for them (been in and out to USVI many times since this started and BVI twice). I agree that the ferries absolutely will not let you bird without a green QR code and proof of your test results (PCR or antibody). Last time I flew back from EIS to STT it was the same - no boarding without QR code and test results.

Water taxis I assume would be the same - they certainly don’t want to get into a problematic situation with USVI customs that affects their future relationship.