With the increase in population and commercial development, urban development has led to a decrease in natural vegetation and an increase in solid surfaces, which negatively affect the environment. Maintaining green spaces in cities is emerging as a critical intervention for improving living conditions. This research, conducted in Thessaloniki, revealed that citizens face problems in using green space, which needs to be addressed. Through questionnaires distributed online, we examined citizens’ concerns about urban green space, including the peri-urban forest of Thessaloniki and its cities. The need for regeneration and new green networks is highlighted, as well as the importance of citizen participation in the management of these spaces at the local level. The analysis of the data results in proposals for action, including the regeneration of green spaces, their interconnection with cycle paths and pedestrian walkways, and the creation of a network of applications to inform citizens. These proposals are important for improving the environment and enhancing sustainability in urban development.