Since knowledge on Descriptor 11 in Portuguese marine waters is still limited, an inventory of background information was compiled, in order to gather available data on underwater recordings, noise-producing human activities and distribution of sensitive species. This report intends to explain the development process of the inventories and to summarize the state of the art of Portuguese waters. Marine anthropogenic activities are broadly distributed in Portuguese waters as are many sensitive species, meaning that regulate noise and monitor potential impacts in marine organisms should be a priority. In Portugal, monitorization of underwater noise has been scarce, thus, data on recordings is limited and it is not always possible to characterize anthropogenic activities to their fully extent. Future studies should focus on long-term monitorization of underwater noise and studying the impact of noise on different taxonomic groups. Directives that regulate underwater noise levels will take time to develop, and an important step to achieve that goal is promoting discussion between stakeholders about impacts of noise on marine environment.