You can reach the Krka natural park by boat from the town of Šibenik. There are different types of tickets allowing you to visit several parts of the park and certain historic sites. The lake crossing is very pleasant.
At the entrance to the park there are small shops offering sandwiches, hot-dogs and crêpes, thankfully I had prepared a little picnic and I found myself a calm spot far from the crowds at the entrance so I could eat in peace.
Following on from this, you can wander at your own pace along the hiking trails across the park and discover the Skradinski Buk waterfalls. In total there are 7 waterfalls in the park. After making the most of the beauty of the nature, I retraced my steps and went near the first waterfall. One can swim in this part of the lake.
To sum up, the natural park of Krka is fantastic to spend a relaxing day in and full of discoveries, in the heart of nature. It's a very important part of a trip to Croatia !