This project was completed by the Coastal Environmental Baseline Program (Coastal and Freshwater Ecology Section) in the Newfoundland and Labrador Science Branch of Fisheries and Oceans Canada (DFO). From 2018 to 2022 baseline biological and physical data were collected in Placentia Bay using Atlantic Zone Monitoring Program (AZMP) and Cold Ocean Productivity Experiment (COPE) protocols. Complementary data were collected in the bay using moored CTDs. Where possible, sampling was conducted monthly at 4 sites between May and November to capture broad scale spatial and temporal trends. Additionally, data were collected bi-weekly in April and May, and monthly from June to September at one of these sites to capture finer scale temporal trends, such as spring blooms, in collaboration with Dr. C. McKenzie. Phytoplankton were collected using vertical net tows and niskins. Zooplankton were collected using vertical net tows. CTDs were used to collect physical and biogeochemical water column data including temperature, pressure, salinity, depth, chlorophyll-a, turbidity, dissolved oxygen, pH, photosynthetic active radiation (PAR), fluorescent dissolved organic matter (FDOM), and conductivity. Water biogeochemistry data were obtained by collecting water samples with niskins at depths of 5, 10, 20, 30, 40m, and 10m above bottom to measure nutrients, chlorophyll-a, carbonates, and particulate organic carbon and nitrogen (POC/PON). Additionally, eDNA samples were taken at each of the 4 sampling sites. This record contains the geographic locations of the sites, and information on the timing and type of data collected at each site.