travel from venice to croatia

Is it easy to get to Porec (Croatia) to Venice?
I'm going to Porec, in Croatia for a week in September and have heard that several companies Tourism is responsible for a coach / ferry ride to Venice for about £ 50/60 each. As someone who hates organized trips and much prefers to do these things with my own, I was wondering if anyone else has done this trip themselves. This time I'm traveling with people who prefer their vacations to be planned for them, even those who eat in restaurants (Grr!) I'm trying to show them a better, cheaper alternative. Does anyone have any recommendations for companies ferry? Is it reasonably easy to arrange – and any idea of cost per person? Thanks
The ferry would be my first bet, but a walk of two hours by bus to Trieste and after a few hours on the train is not too bad – good view of the Istrian countryside, but the ferry would be my bet and not too bad a walk. I guess I should to go from Pula, Rijeka, or no?
Italy venice Water Taxi