Shipbuilding belongs to the heavy industry sector of the global economy. As the pressure increases to control and improve the sustainability of such operations, shipyards and ship operators alike see the need to monitor and assess the various sustainability aspects related to their operations and to be able to develop the required reporting capabilities. The ESY sustainability platform presented in this paper is an approach being developed as part of the ESY (EcoShipyard) project. It considers and integrates multiple key aspects of sustainability, such as energy and resource consumption and emissions, material utilization and circularity or regulatory compliance. The primary concept of this development is to provide a cloud-based shipyard production and operation monitoring and assessment platform, which operates based on a digital twin of the shipyard facilities, processes, products and resources and which is complemented by the real-time data provided by a broad range of data sources. Based on this rich data collection, the Plan-Do-Check-Act (PDCA) methodology (as specified e.g. by ISO 50001) can be applied, providing means to assess the current status, to predict the effects of planned modifications and to monitor the results after implementing modifications. A further relevant result is the provision of reliable data to be used for reporting, e.g. to comply with CSRD or ESRS regulations. We review the requirements of material passports as a means to improve circularity of resources and of the sustainability accounting process that must be met for compliance with e.g. the Greenhouse Gas Protocol and how they need to be addressed in the context of a made-to-order type industry like shipbuilding.