This dataset contains optical (absorption, scattering and radiance) as well as environmental data (temperature, salinity, concentrations of suspended particulate matter (SPM) and Chlorophyll) collected in optically complex Norwegian fjords (Hardangerfjord, Gaupnefjord and Lurefjord) as part of the EcoSens project. Hardangerfjord was sampled during a coccolithophore bloom in 2022, and again during the following year without a visible bloom. Gaupnefjord was visited during a period of high glacial meltwater influx. Lurefjord is a fjord with high concentrations of colored dissolved organic matter (CDOM). This dataset is divided into separate folders containing metadata, CDOM absorption, particulate scattering and absorption, phase functions, radiance, and irradiance spectra, and should be viewed in tree folder structure.