The CoCliME project co-develops and co-produces bespoke, proof-of-concept or prototype marine ecosystem climate services and a transferable framework for climate services development, to support informed decision making relevant to climate change-related ecological and socio-economic impacts across different coastal regions. The consortium brings together a transdisciplinary team of natural- and social scientists, decision makers, and users of climate services that will dynamically interact to identify common priority climate change-related vulnerabilities and solutions in six European coastal areas. In these case studies from the North Atlantic Ocean and the Baltic-, Black-, Mediterranean-, North- and Norwegian Seas. CoCliME focuses on coastal ecosystem status indicators, e.g. harmful algal blooms, biotoxins, pathogens and microbial biodiversity, that can be markedly influenced by climate change and have direct impacts on human health, economic prosperity and social wellbeing. Available global IPCC climate change scenarios are selected and refined to adapt to the specific regional requirements of the case study area. Here we define the first project results of a hindcast data study, including preliminary analyses of the modelling component of the North Sea case study. In addition, we present a coordinated CoCliME sampling initiative to document the presence or absence of potential toxigenic representatives of the benthic dinoflagellate genera Ostreopsis, Gambierdiscus, Coolia and Prorocentrum at various sites of the case study areas