Once you arrive on St. John you can get the free Activity and Road Maps everywhere, right at the ferry dock or at the information booth next to it. They are free and contain a lot of useful information about beaches, activities, bars, restaurants and shops. Finding a good map online is not easy.
The best St. John Online Map ever
is by the NPS and can be found here. Because it is in Flash, search engines don’t find it. But now you know where it is!