Erlaufsee is another gem of the Steiermark near Mariazell. It is a wonderful place to cool off on…read morea hot summer day. The views are amazing, the water is clear and there is no entrance fee. Parking will set you back a few euros and you should secure a place early on the weekends especially. There is a grassy area and rocky beach, slides and diving boards and the chance to rent paddle boats, paddle boards (unfortunately only 2 boards), and motor boats on the Steiermark side. On the Niederoesterreich side there is no beach, but a walking path and other boat launches, most are private though. I think there is also a cafe, but the restaurants and stands are on the Steiermark side. Or you can pack up a cooler and chill out without extra costs.