As part of research projects in Environment and Climate Change Canada, historical physical limnology observations have been collected in Canadian Lakes since 1968. These observations include one or more concurrent measurements of water temperature profiles, directional velocities (east-west and north-south directions) profiles, conductivity, turbidity, and dissolved oxygen at different depths, in Lake Erie, Lake Ontario, Lake Huron, Georgian Bay, and Lake Winnipeg. These observations are in raw (original) and organized formats. The organized observations have gone through basic QA/QC processing steps (e.g., excluding air-water periods or anomalies in the records). Both raw and organized observations are shared here.