For those who are not in a hurry it's a pleasant way of spending a day. Get off at the station Harmanecka jaskyna. Check the timetable at the railway station in Banska Bystrica, as the train does not go very often. The temperature inside the cave remains a constant 6 degrees Celsius throughout the year. Wear long trousers and bring a jacket or warm sweater, even if the weather outside is warm.
Passageways are well maintained but often slippery.
Heavy shoes are recommended. Don't forget about a 40-minute climb to the cave. The way down is quicker. It takes about 20-30 minutes. You should allow 3-4 hours for the whole visit.