Abstract. Urban parks are a vital part of cities around the world, accepting millions of visitors daily. However, in most cases urban parks do not enjoy the technological support that could enhance visitor experience and facilitate park administrators. VR-Park is a project that addresses the above issues and uses as a case study the “Pedion Areos” park, a prominent park in Athens, Greece. It comprises a mobile phone application used by the park visitor, and web-based applications used by the park administrator. This paper focuses on Park Visitor Activity, an innovative application used by the park administrator to collectively assess visitor movement and activity in general. The movement of visitors inside the park is collected and analyzed, to provide patterns of usage of the park areas: spots where people gather, pathways that are used the most, months of the year / time of day when visits have a peak, etc. Such information is invaluable for taking informed decisions about the management of the park. Comprehending how people tend to move and how they use an open area can be very useful in a wide spectrum of cases that go beyond urban park administrators. However, implementing such an application involves several challenges, which are discussed in this paper.