In this paper, we present PSiS (Personalized Sightseeing Tours Recommendation System) Mobile. PSiS Mobile is our proposal to a mobile recommendation and planning support system, which is designed t In this paper, we present PSiS (Personalized Sightseeing Tours Recommendation System) Mobile. PSiS Mobile is our proposal to a mobile recommendation and planning support system, which is designed to provide effective support during the tourist visit with context-aware information and recommendations about places of interest (POI), exploiting tourist preferences and context. We also provide a state of the art on tourism mobile device applications and describe some of the main problems encountered on the development of such applications. Finally, we present a study to discover which is the lightest and fastest way to exchange information between a server and a mobile client in order to minimize the mobile device limitationso provide effective support during the tourist visit with context-aware information and recommendations about places of interest (POI), exploiting tourist preferences and context. We also provide a state of the art on tourism mobile device applications and describe some of the main problems encountered on the development of such applications. Finally, we present a study to discover which is the lightest and fastest way to exchange information between a server and a mobile client in order to minimize the mobile device limitations