I will find myself in Monfalcone for work in a couple weeks. Last time there (2009) I had some spare time afterwards to visit some family and friends in Ljubljana. This time, I'd like to head to the coast if I can. I'd prefer not to rent a car, and am curious if anyone knows if there exists any ferry service between Monfalcone and the Solvenian Istrian cities. Does not matter to me if it is Portoroz, Piran, Koper, or Izola, as I will likely only have a day or two and have not been to any of these locations yet.
Thanks in advance for your help!