You're very late for a rental car. LocalSailor's list is good. There are some newer companies you can try also.

http://lioneljeeprentals.com/
https://aquariusstjohn.com/st-john-car-rental/

Here is another list: https://newsofstjohn.com/car-rental-companies-on-st-john/

Fall back is to rent on St. Thomas and take the car ferry.

Cheers, RickG


S/V Echoes, 2003 Beneteau 423
Grenada