Urban natural systems depend not only on the presence of green and biologically active areas, but also on the continuity of the connections between them. In Polish spatial planning, local natural system connectors may be identified in policy documents, although they do not constitute a separate legal category or an independent form of nature conservation. This study examines the legal and planning status of such connectors and identifies the instruments that can be used to protect their spatial and functional continuity. The research applies a qualitative legal and planning approach, including legal-dogmatic analysis, content analysis of planning documents, and a comparative assessment of selected Polish cities. Białystok, Poznań, Lublin and Warsaw were analysed because they represent different approaches to the conceptualisation of urban natural systems and their connecting elements. Particular attention was given to the Białystok model, in which natural system connectors are identified as a separate planning component. The results show that the effectiveness of protection depends mainly on the extent to which the functions of these connections are translated into binding land-use and development provisions. Local spatial development plans provide the strongest direct instrument for such protection, while strategic, analytical and procedural tools play a supporting role. The ongoing reform of the Polish spatial planning system may strengthen the protection of local natural connections through the General Municipal Plan. At the same time, its zone-based structure may create difficulties in adequately representing narrow linear and strip-like structures. The study therefore highlights an implementation gap between the strategic identification of ecological connections and their legal protection and emphasises the need for a multi-stage approach linking environmental recognition, general planning and binding local regulations.