This dataset contains zooplankton taxa density sampled fortnightly from Windermere North Basin and Esthwaite Water in Cumbria, England. All data are from January 2005 to December 2009. The data available to download comprise the density of all zooplankton taxa identified in the samples in individuals per m2. Zooplankton were sampled from a boat at a marked location (buoy) using a plankton net (250µm), preserved, and counted in the laboratory, to determine the density of identified zooplankton taxa (individual per m2) within each sample. This dataset was created as part of an ongoing long-term monitoring program of Lakes within the English Lake District, which has collected a range of environmental and biological measurements since 1945. Full details about this dataset can be found at https://doi.org/10.5285/39bed192-423a-4bbf-9b97-7d3da8aab445