The DTOcean project is aimed at accelerating the industrial development of ocean energy power generation knowledge, and providing design tools for deploying the first generation of wave and tidal energy converter arrays.The areas of hydrodynamic array layout, electrical infrastructure, operations, maintenance & control, moorings & foundations, and installation & logistics bring critical challenges which must be addressed for the ocean energy sector in order to reach commercialisation. Whilst the current conditions seen in the sector are acceptable for the development stage that the sector is currently primarily focussed on – testing prototype devices – they are not acceptable as the sector moves towards the deployment of medium and large-scale arrays. These factors, if not addressed, have significant consequences for the sector, such as a failure to optimise the design of ocean energy arrays due to neglecting the extra complexities of array designs over single device deployments, and failure to properly understand economic, environmental, or reliability impacts that individual components within an array design can have on the overall project.The DTOcean project brings together an integrated suite of Work Packages to address the challenges that have been highlighted, as the sector progresses from single devices to arrays. The Work Packages will form core elements of progression beyond current state-of-the-art knowledge.Within each work package there will be a significant focus on the economic, environmental and reliability challenges. This will ensure that each step of the design process considers the overall impact of individual Work Package decisions – ensuring environmentally appropriate project development. The result will culminate in a suite of open source design tools for the ocean energy sector.