The authors present recent progress in the development of the British Columbia Marine Energy Resource Atlas (hereafter referred to as the “Atlas”). The Atlas is a web-based geospatial decision support system and was developed to assist marine renewable energy stakeholders with preliminary site selection and feasibility investigations in the rivers and coastal waters of British Columbia, Canada. The Atlas offers a clean and simple interface through which users are able to interact with the underlying geospatial data and customize investigations to fit their specific design and development criteria. The Atlas represents a uniquely flexible and accessible decision support system that can be operated online via a web browser and does not require any specialized geographic information system software. Furthermore, the Atlas is the first marine renewable energy decision support system to offer support for tidal, wave, and river hydrokinetic resources under a common system and interface.