Coastal areas around the world have attracted settlements and human activities since the early stages of the history until nowadays. This has introduced continuous modifications to the natural characteristics of these coastal regions by means of coastal structures and engineering interventions. The design of such coastal structures has evolved significantly since the first quarter of the XXth Century, when more scientific design methods and formulae were developed. Nevertheless, further research is required given the stochastic nature of the environmental loads involved, the remaining uncertainties regarding the response of these structures to the applied loads and the growing impacts of climate change and sea level rise. Four knowledge gaps are identified regarding the “Damage assessment of coastal structures in climate change adaptation”. Based on these, the objectives of this thesis are summarized as follows. First, climate change adaptation: demand for validated upgrading alternatives. Second, damage characterization concepts: demand for unified damage characterization concepts. Third, damage characterization parameters: demand for universal and more accurate damage characterization parameters. Fourth, damage characterization measuring techniques: demand for validating the suitability of innovative survey methods. These knowledge gaps are addressed using physical modelling results from two test campaigns (UPorto deep water and Deltares shallow water tests. In consequence, this study includes the validation of the damage criteria required for a precise assessment of a coastal structure (second knowledge gap), the validation of an universal damage parameter for rubble mound structures (third knowledge gap), the validation of the benefits of innovative measuring techniques when carrying out physical modelling tests (fourth knowledge gap) and the validation of upgrading alternatives for climate change scenarios (first knowledge gap). Thus, it can be stated that with these definitions, parameters and measuring techniques, a complete method for damage characterization of coastal structures is presented. It was also defined how this damage characterization method can be used to precisely and accurately describe the damage to conventional and non-conventional coastal structures. Furthermore, this method was also used to describe the effects of not only current environmental forces acting on the structures but also future and more energetic scenarios. For such future scenarios, adaptation alternatives for coastal structures were evaluated and berm configurations are recommended for their upgrading. Future research is needed in order to evaluate, adjust and generalize the conclusions made in this thesis, considering additional structure configurations and environmental loading conditions.