This dataset provides the conductivity, temperature and depth (CTD) measurements from the fixed-depth CTD sensors mounted on a full-depth mooring deployed by the SWOT prelaunch field campaign. The campaign was designed to test the performance of several instruments/platforms in meeting the SWOT Calibration/Validation (CalVal) requirement. It was conducted near the SWOT CalVal crossover location, about 300 kilometers west of Monterey, California between September, 2019 and January, 2020. These fixed-depth CTDs cover the full depth from the ocean surface to the bottom. The surface buoy is equipped with a Global Positioning System (GPS) https://doi.org/10.5067/SWTPR-GPS01. There is also an adjacent bottom pressure recorder https://doi.org/10.5067/SWTPR-BPR01. The campaign also deployed another two CTD moorings, a slocum glider, one bottom pressure recorder and one Pressure Inverted Echo Sounder.