This dataset contains measurements of physico-chemical parameters, biofilm, and watershed characteristics from subarctic lakes and streams in the Narsaq area, Greenland, collected in August 2022. Water samples were collected and analyzed for temperature, conductivity, alkalinity, and nutrient concentrations. Biofilm samples were collected from stones, with chlorophyll a (Chl a), ash-free dry weight (AFDW), and carbon-to-nitrogen (C:N) ratios measured. Algal pigments were analyzed using HPLC for taxonomic composition. Watershed delineation was performed using a digital elevation model (DEM), and vegetation greenness was quantified via the normalized difference vegetation index (NDVI) using Sentinel-2 satellite imagery. This dataset contributes to understanding the environmental drivers of biofilm biomass and community composition in Arctic freshwater ecosystems.