This paper details a resource and constraint assessment for tidal stream deployment sites around Pembrokeshire, Wales. Based on a minimum peak spring current of 2ms-1 , seabed depth and gradient constraints, four sites, providing a total area of 48.3km2 were identified. Using the significant impact factor method, it is estimated that these sites could provide 1.3TWhrs per year. Constraints such as port proximity, fishing activity and SAC habitats were considered. It is suggested that the most promising area for first stage turbine array deployment is the Bishops and Clerks area.