Cross-border marine or maritime spatial planning (MSP) in the Baltic Sea region (BSR) and in the precursor project Baltic SCOPE has so far mostly focused on coordinating planning in the exclusive economic zones (EEZ) of each country. Linking planning across national borders to include territorial waters and the land side as well is recommended and necessary, e.g. for transport planning or for ecosystem based management. It is even requested by the EU-MSP directive, asking Member States to consider land sea interaction (LSI) when drawing up their plans. Such a perspective will bring new, interesting perspectives but, according to our scoping, also imply challenges in terms of: