Where is the port in Venice?
 

I've been to Venice twice but never saw where the ferryboat port is. I'd be arriving in Venice at the Santa Lucia station but am unsure how to get to the port from there.

It's on the west side of Venice. There are several berths, depending on which ferry you are taking. You take a vaporetto from the train station to the ferries.

http://www.actv.it/english/navigazio...iffe_vaporetto

Which ferries do you mean? Ferries to Greece (ANEK and Minoan Lines) use the Stazione Marittima which is also used by cruise ships. You can take a taxi by road from Piazzale Roma.
Boats to Slovenia and Croatia normally use the San Basilio terminal which is served by vaporetti.

Thanks for the answers, we're going to Croatia which I should have mentioned in the question.

Here's the link to Venezia Lines Ferry web site, with detailed directions on how to get to the port.

www.venezialines.com/eng/ports_pocetna.asp