Rovinj to Plitvice National Park

Don't think so. We drove from Motovun to Plitvice and I recall it being about 4+ hours. Motovun is a little east of Rovinj, so it's arguably closer - although we were on small roads for a little while, so thats probably a wash. Unless you want to spend 8-10 hours that day driving back and forth, I don't think it's practical as a day trip.

To visit Plitvice as a day trip from Rovinj with a one-day car rental and no overnight, you'd need to pick up the car early and depart Rovinj by 8:00. With drive, visit, dinner and return, you probably wouldn't get back until close to midnight and would need to be up early the next day to return the rental car. Hotels at and sobe near the park aren't terribly expensive, so I'd recommend an overnight if you plan to visit Plitvice. I you decide to make the trip, I believe Uniline may be the only car rental company with an office in Rovinj (most are in Pula and Porec). I rented from Uniline in 2008 with good experience, and they'll bring the car to you if arranged in advance. Of the hotels at the park, I like Hotel Jezero, and the grilled meats and fish (fresh trout) at the nearby Licka Kuca restaurant make for a memorable meal.

There's also an Oryx rent-a-car office in Rovinj (by the harbor). We picked up our car from them in May 2012. But I agree it's not a reasonable day trip from there to Plitvice.

That would be a long day. When we were there in 2010, we flew in to Venice, rented a car for our two-week trip, and drove to Rovinj. After our stay in Rovinj, we drove to Grabovac, Croatia and stayed in Rick Steves recommended House Tina for one night which was only about 5 miles from Plitvice NP. I believe you will have a more enjoyable visit spending the night versus driving back and forth as a day trip. The B & B was very reasonable too. Enjoy your trip to Plitvice NP!!

Thank you to everyone for your advice and comments. Much appreciated! Melanie