Trójmiejski Park Krajobrazowy (Tri-City Landscape Park), established in 1979, is one of the oldest landscape parks in Poland. It covers almost 20,000 hectares on the edge of the Kashubian Lake District moraine upland, within the Tri-City agglomeration. Forests, mainly beech, cover over 90% of its area, and the most valuable parts are protected in ten nature reserves. We prepared a mobile app for Android phones that presents the park's natural, cultural and landscape assets. Thanks to GPS, the nature reserves and natural monuments described in the app are easier to find on site.