Best thing to do in lubjiana

Love Ljubljana! My husband and I spent a few nights there without children. But I can imagine that children might enjoy the walks offered by the tourist office and would certainly enjoy a trip to the castle on the hill. A highlight for us was a private food tour, but I don't imagine this is a child-friendly event. I hope you have a wonderful time!

The caves nearby are very interesting! They probably would love that activity!

From a local: https://myljubljanatour.com/blog/things-to-do-in-ljubljana-with-kids/

Škocjan Caves would be great if you had more time, but if you only have one day, I would stick with Ljubljana. If you can eek out another day, the Caves are Lord of the Rings quality. In one massive cavern, I wanted to grab a staff and slam it into the ground, while shouting in my best Gandalf voice, "YOU SHALL NOT PASS!"