The rapid growth of e-commerce and urban freight flows has intensified the need for sustainable last-mile logistics solutions. This paper explores the potential of the Physical Internet (PI) as an innovative and systemic framework to address the inefficiencies and environmental impacts of urban freight distribution. Drawing inspiration from the architecture of the digital Internet, the PI conceptualizes logistics as an open, standardized, and hyperconnected network. Through detailed analogies between digital and physical networks, the paper outlines how logistics nodes – such as Urban Consolidation Centres (UCCs), microhubs (MHs), and mobile microhubs (MMHs) – can operate as intelligent routers to facilitate modular, multimodal, and collaborative last-mile deliveries within a comprehensive framework that integrates real-time flow allocation hierarchies, transport mode combinations, and stakeholder interoperability to optimize last-mile distribution. Key enabling technologies, including IoT, AI, and blockchain, are examined as critical components of PI implementation. The study, with a novel application of a PI-based layered architecture to last-mile delivery, highlights the need of real-world experimentation and the development of inclusive governance models to foster the widespread adoption of PI-based logistics in urban contexts.