The “Optimal Design Tools for Ocean Energy Arrays” or DTOcean project, was a FP7 (Call ENERGY 2013) European Project, whose objectives were the acceleration of the industrial development of ocean energy power generation knowledge and providing a performant design tool, in the form of a software package, for deploying the first generation of wave and tidal energy converter arrays. The software generated by the DTOcean project automates the design of a feasible array of ocean energy converters (OECs) for a relevant geographical location and technology type. The design process is modularized into the following stages: Hydrodynamics, Electrical Sub-Systems, Moorings and Foundations, Operations and Maintenance. The software also evaluates each stage of the design, and the design as a whole, using three thematic assessments, which are: Economics, Reliability and Environmental. The challenge and ultimate goal of the project was to optimize the designs created by the software, against a suitable metric, chosen as the levelized cost of energy (LCOE).