Large seaport hubs in Northwestern Europe are aiming to develop as circular hotspots and are striving to become first movers in the circular economy (CE) transition. In order to facilitate their transition, it is therefore relevant to unravel potential patterns of the circular transition that ports are currently undertaking. In this paper, we explore the CE patterns of five Belgian seaports. Based on recent (strategy) documents from port authorities and on in-depth interviews with local port executives, the circular initiatives of these ports are mapped, based on their spatial characteristics and transition focus. The set of initiatives per port indicates its maturity level in terms of transition towards a circular approach. For most studied seaports, an energy recovery focus based on industrial symbiosis initiatives seems to dominate the first stages in the transition process. Most initiatives are not (yet) financially sustainable, and there is a lack of information on potential new business models that ports can adopt in view of a sustainable transition. The analysis of CE patterns in this paper contributes to how ports lift themselves out of the linear lock-in, as it demonstrates that ports may walk a different path and at a diverging speed in their CE transition, but also that the Belgian ports so far have focused too little on their cargo orchestrating role in that change process. Moreover, it offers a first insight into how integrated and sustainable the ports’ CE initiatives currently are.