An alternative to Plitvice Lakes, Krka lets you follow winding paths through terraced, cascading waterfalls. Unlike Plitvice, there are places in Krka where members of the public are allowed swim and the Skradinski Buk waterfall (pictured above) has become one of Croatia's most famous sights.
Krka was very full when we were there, but swimming beneath the main waterfall was wonderful with deep, cool water and beautiful views. The rocks were a bit slippery so wear reef shoes. There is also the option of taking a boat excursion to Visovac Island in the middle of the river, and visit the Franciscan monastery there.
We did a day trip to the Krka Falls from Zadar, which was very easy – there is a direct bus to Skrakin, and you can take a boat from there to Krka National Park.