The Park Krajobrazowy Pojezierza Iławskiego (Iława Lake District Landscape Park) was established in 1993 on the border of the Warmian-Masurian and Pomeranian voivodeships. It protects a young post-glacial landscape with more than forty lakes, including Jeziorak – the longest lake in Poland (27.5 km) – and Jezioro Jasne, known for its exceptionally clear water. We created a mobile app for Android phones that serves as a guide to the park. With GPS it helps visitors find interesting places in the field and discover the nature of the Lake District. For the same client we also produced the ‘Wzgórza Dylewskie’ (Dylewo Hills) app. The app is available in Polish, English and German.