I will be in Rovinj in mid July after a rather hectic 15 day tour of the Dalmatian Coast. I need to go to Venice on the 11th morning and read somewhere that its easy to take the ferry across. But the Jadrolnija does not travel this route. Any idea which ferry Co. it would be or is it possible by bus...which probably be more scenic. Thanks .

Ferry leaves on 11th from Porec at 8am but you may find it easier and cheaper to take the bus from Pula.
www.pulainfo.hr

We got a bus from Pula to Trieste, about 3 hours. I think there are about 3 a day. From there you can get the train to Venice. Don't know about a ferry.

Boats are run mainly as day trips from Istria to Venezia. On 11 July, Venezia Lines (http://www.venezialines.com) has a sailing from Rovinj at 0700 to Venezia.
The bus station in Trieste (www.autostazionetrieste.it) has a timetable showing morning departures from Rovinj at 0540 and 0740 to Trieste, amongst others. At Trieste, the bus station is adjacent to the railway station which has hourly trains to Venezia.

The ferry was great. This past June, we hopped on at 7 a.m., made a quick stop in PIran, Slovenia, and got to Venice a tad after 11 a.m. Be sure and get a straw for your coffee, however.

Thanks everyone for the useful info. Still not decided between bus or ferry. But will take it as it comes. Thanks....Katie

we took the local bus from Rovinj to Trieste and then the train to Venice. very easy. the bus station is next door to the train station in Trieste.

I'm planning to trip from Rovinj to Venice, but i dont know do I need passport when crossing to Slovenia or Venice from Rovinj ?

Passports are required for international journeys from Croatia (including trips to Slovenia or Italy).