MetaCity is an innovative smart city and urban concept that champions open innovation through digital platforms and social networks. It goes beyond being merely a research idea or a single technical advancement, instead embodying a holistic approach that encompasses innovators, innovations, users, and facilitators within a new narrative of innovation ecosystem. Metacities rooted in the Living Lab principles, i.e., the inclusion of early (and continuous) engagement of all relevant stakeholders, value co-creation for all participants, openness and transparency, an iterative process (inclusive to receive and apply feedback), real-life experimentation, the distribution of decision-making power, and the identification of stakeholders' needs, motivations, and expectations to promote social inclusivity. Accordingly, MetaCities can be defined as the extended version of traditional and technically oriented smart cities by integrating Living Lab principles to foster inclusivity by balancing the social and technical aspects. To achieve the main objective of this initiative, the MetaCities project —Connecting Pockets of MetaCity Excellence around the Baltic Sea Region, funded by the European Commission under grant agreement 101134225. The project aims to accelerate, consolidate, align, and leverage the existing MetaCity and Smart City initiatives of the partner regions. Through these efforts, the project seeks to build the world’s leading connected MetaCity Region across the Baltic Sea (BSR).