Isn't Civitavecchia where the cruise is docked?
Sorry I don't understand either your question or the problem. The ship docks, I understand, in Civitavecchia and that is where you join it so where are you coming from ? Maybe you should RING your agent to get a definitive answer. Regards....Neil Dow.
if arriving by train then you can get taxis to the cruise berths as at say southampton. the journey from rail station to cruise berrth takes about ten mins
i think to calrify other answers, Costa cruises start from Civitavechia, and many people fly to Rome independently and make their own way to the shi.
From civitavecchia train station walk along the front with your luggage keeping the sea on your left hand side - you will then get to a bus stop where the 'free' bus runs you to the ship. Or catch a cab.