Just for riding through Austria Wessie.Assuming this is for the trip to Croatia, then you will also need a vignette if your route uses a motorway in Slovenia. Again, like the Austrian one, they do short term ones. Also make sure you use the official website if buying online. https://evinjeta.dars.si/en 8 euros for a week
Although, as Slovenia is a smal country with some fantastic scenery, I highly recommend riding over the Vrsic pass from Kranjska Gora to Bovec and then down through the Soca valley to Postonja before hopping over the border into Croatia.
And thanks lads