Time series data of physical oceanography (seawater conductivity, temperature, pressure, salinity) were obtained from mooring M3 on the upper part (750 m isobath) of the continental slope, just east of the Filchner Trough in the southern Weddell Sea in February 2017 - February 2021. The mooring was deployed during the WAPITI expedition on James Clark Ross (JR16004), and recovered during the COSMUS expedition with Polarstern (PS124). The attached archive contains data from 1 RCM7 (21 meters above bottom (mab herafter) and sampling interval (sint hereafter) 2h), 13 SBE56 (22,56,81,106,159,184,6508,260,285,310,335,360,385 mab, sint: 120 s), 4 SBE37 (31, 134, 209, 410 mab, sint: 600 s), 1 SBE39 (435 mab, sint: 900s). Mooring diagrams and information about data processing are provided.