Abstract: The goal of this report is to improve the communication between numerical modellers and the ocean colour community. It provides non-expert accessible information about both ocean colour and biogeochemical and ecosystem modelling. The report discusses methods of model skill assessment using ocean colour products, introduces and highlights case studies of data assimilation involving ocean colour products, and provides examples where models and ocean colour are used synergistically to better understand processes and trends in the ocean’s ecosystem and biogeochemistry. Additionally, the report explores how models can help inform on ocean colour, with the goal of fostering further use of models in ocean colour studies, in helping elucidate uncertainties, and in algorithm development.