The phenomenon of coastal erosion deeply affects the Portuguese coast. The beach-ocean system cannot be considered in a situation of morphodynamic balance because the beaches are open systems, and their sediments are being constantly transported. Winds, tides and waves are the main erosive actions, but there are other causes of anthropogenic origin that influence erosional processes. This work aims to evaluate the morphological changes of short time scale, considering different waves and tide conditions at Ofir beach, located at the NW Portuguese coast. This beach was intervened with geosynthetic cylinders as a coastal defense measure. The work is based on a monitoring program, using high-precision topographic surveys with DGPS equipment. The application of geosynthetic cylinders on this beach proved to be efficient in the analyzed period and in the verified conditions of waves and tides, although they have suffered erosion and have been exposed.