The National Oceans and Coastal Information Management System (OCIMS) of South Africa is a large, integrated IT system for enhancing oceans, coastal and maritime governance, and supporting sustainable economic utilisation of ocean and coastal resources. This article is a case study, describing how a range of Free and Open Source Software are deployed to generate the Open Standards based core of this federated system for providing decision support applications in addition to data and information management, access and dissemination services. This article demonstrates the importance of modern software development and deployment approaches in constructing the OCIMS core and easing the integration process with other systems in the federation. Finally, this article discusses some lessons learned and reflects on the lineage of OCIMS architectural choices and how these approaches may need to adapt to changing computing environments