The closest ferry from the cruise ship to St. John leaves from downtown Charlotte Amalie. If you get off the ship early enough, you can catch the first one out at 9 am. The last one back to CA gets in at 4:30 with plenty of time to get back to the ship. If you can't make the 9am, the next is at 11am. You may want to take a taxi to Red Hook. There they leave and return on the hour, and you will have to factor in the 1/2 hour or so taxi ride to get back in time!
Ronnie

My very senior parents want to take a ferry from St. thomas to St. Johns and then have a quiet tour of the city and island.....low activity level. Do you have suggestions of tours available on the island that could start near the ferry docking. thanks

St John no "s". When you get off the ferry go immediately to your left.....well, after you get through the security gate. There will be a bunch of taxies. Tell someone what you want and they will be more than accomodating. Depending on the "seniorness" of your parents, they might even be able to walk around Cruz Bay. If not just ask and you'll get tour in a taxi and they'll be more than happy to take you to some wonderful overlooks for viewing of the beaches

I will be down in St. Thomas in Oct for some fishing out of Red Hook. My friedn said a place to stay is over in St. Johns and then take the ferry over to Red Hook. Does anyone know the times the ferry starts? I assume we will be departing the dock in the morning and need to be sure the ferry is running before I book a room on St. John's.

https://www.vinow.com/general_usvi/interisland_ferry/

This link provides ferry details between St. Thomas and St. John.