Ocean color indices derived from EUMETSAT high resolution (300 m) Sentinel-3 OLCI Level-2 sea water reflectance data are published operationally to help in the assessment of the overall water quality and ecological health in the sea around the Maltese Islands. This is an experimental service to assess the incidence of sea surface algal concentrations based on algorithms available in the literature without direct calibration and validation that takes into account the influence of several site-dependent factors.