Honestly I don't know, UM should work in Croatia as well as Travelsim and both have free incoming calls. In Slovenia both UM and Travelsim don't have free incoming calls, but Travelsim is cheaper for short calls. If you often go there you can consider a local simcard, they are rather cheap nowadays (expecially compared to the past). I'm in Slovenia every month but I didn't buy a local card yed even if I shoud!
