The paper discusses the influence of slope porosity and model scale for a low reflective vertical quay. Physical model tests were carried out in the small and large scale facilities at Universitat Politècnica de Catalunya, in Barcelona, with regular waves. Matteotti (1991) conducted experiments for similar kind of quay. The results for small scale agree with the Matteotti’s ones, but the large scale tests lead to smaller reflection. This is due to the presence of scale effect at small scales. The authors applied the Burcharth et al (1999) approach to treat scale effects, as shown in the paper.