Over the next decades, wave energy aims to become a commercially viable source of energy. For this purpose, a complete understanding of the wave resource characterisation is needed. In this context, the International Electrotechnical Commission (IEC) has developed a technical specification for the assessment of the wave resource, IEC-TS 62600-101: Marine energy-Wave, tidal and other water current converters-Part 101: Wave energy resource assessment and characterisation (IEC-TS). IEC-TS classifies resource assessment studies into three different categories: reconnaissance, feasibility and design. The requirements for the model setup (mesh resolution, boundary conditions) and the effort (validation process, computational times) vary considerably from one class to the other. Accordingly, the main goal of this work is to explore this methodology using the Irish West coast as a case study. Overall, it was found that the methodology proposed performs well, offering a detailed characterisation of the resource; however, with the aim of making the technical specification more manageable, some aspects related to the validation and model setup procedures may be revisited for future editions.