renting a car in Slovenia and getting to Croatia

Laura, it might help if you could post your general itinerary. How much time do you have and what do you want to see?

Typically, the ideal "connecting cities" between Croatia and Slovenia for renting cars in both countries (assuming you start in Slovenia with one car and pick up another car in Croatia) Ljubljana to Zagreb (train or bus), Ljubljana to Rijeka (train) or Ljubljana to Istria (bus). Alternately, you could drop your Slovenia car on the coast say near Koper and then take a bus or transfer service (e.g. GoOpti) on to Istria - say to Rovinj or Porec.

Another approach is to start in Zagreb, rent the car there, drive to Slovenia, drive back into Croatia down to say Dubrovnik and return the car there. That fulfills the "drop in the same country" requirement.

To get an idea of what the one-way drop fees might if you say drop the Slovenia car in Croatia, check out the website of the rental car company Sixt and try some city pairs like Ljubljana and Zagreb or Ljubljana and Dubrovnik. You'll find that the drop fee for Zagreb is less than the drop fee for Dubrovnik, which is much further away from Slovenia.

We did this last year! We took a train into Ljubljana after a visit to Austria and spent a couple of days before we rented a car. Then we just walked over to the Grand Hotel Union and rented a car from Budget. We had reserved in advance - it seems like they might not keep a lot of cars on hand. We then drove to Lake Bled and the Soca Valley for a couple of days, and returned the car to the hotel when we were done. We had a nice lunch in Ljubljana and then walked to the train station to take the 3pm train to Rijeka in Croatia (arrives about 6pm). From the train stationin Rijeka, we were able to walk to the Oryx Rental Car agency over at the harbor front. Again we had reserved and they had a nice new car ready for us. We rented a wifi hotspot for a small additional charge and it was so worth it for GPS navigation. We drove to Rovinj that evening. We had the car for ten days and returned it at the Dubrovnik Airport at the end of the trip. Since we were traveling to both Bosnia-Herzegovina and Montenegro with the car, we let them know in advance and our papers were all in order.

Excellent, thanks so much, that's exactly the kind of set up we'd be looking to do! Much appreciation :)

Per my recollection the additonal drop fee was like $500 (in 2009). We also struggled with this. We were in Lake Bled. Rented a car for the Julian Alps (if you are prone to car sickness, take Dramamine). Then I struggled HARD with how to tie in Plitvice Parks on the way to Split. Eventually I relented to the fee and dropped the car in Dbrovnik to avoid a run around of car exchanges.

I did almost exactly the same thing as Tigerfan in 2015: train from Ljubljana to Rijeka, walked to the Oryx rental car office, and drove to Rovinj. FYi, if you don't mind buses (I like trains and dislike long bus rides), you could just take a bus from Ljubljana directly to Rovinj and rent a car there - Oryx has an office there as well. I reserved my Oryx car through EconomyCarRentals to get a good rate.

Just this last May, I rented a car for a day in Ljubljana to visit some small towns in Slovenia and do some scenic drives. I rented from Avant Car in the center of town. A few years ago, I rented from Sixt at Ljubljana train station. I'd rent from either company again. Ljubljana is small enough that it's pretty easy to walk to most any rental car place near the center of town or close to the train/bus station.

There's really no need to rent a MiFi for GPS, though. A smart phone works for GPS navigation without any internet data signal. All you have to do is download the maps needed ahead of time. Google Maps for example lets you download "offline" maps ahead of time on WiFi. I drove with Google Maps offline in Slovenia in May with my phone in airplane mode. There was an occasional glitch, but it worked surprisingly well, and I would have been fine driving without a working mobile phone. (My phone had data but I kept it off most of the time while driving to save data.)

We toured both countries in 2015. We had often rented a car "open jaw" in other countries and paid extra to pick up in Austria and return in Switzerland (as an example). However, when looking into this for Croatia/Slovenia, it was a larger than usual fee (I don't remember how much but you can certainly call AutoEurope or whomever and ask what your options include). We adjusted our trip to drive from Ljubljana to Zagreb (a few hours) with a quick overnight in Zagreb so we could return the car there. I seem to remember others when I was planning my trip had taken a train from Istria into Slovenia to rent a car there after returning their Croatia rental.

Enjoy. You will LOVE both countries.

Picked up car from Styx at the AP in Lj and dropped it off in Split. Was back in 2008 thought, but what I remember is that what ever extra we paid, it was worth it. Did not need car between Split and Dub. This was a Great trip! You can check out our pics at our personal blog.
http://www.gadtravel.com/2008/10/slovenia-and-croatia.html