Salinity data from sea ice samples taken during MOSAiC leg 2 (PS122/2). Sea ice samples were taken from Fort Ridge and surrounding undeformed first-year ice (FYI). Sea ice cores were extracted using a 9 cm inner diameter ice corer (Kovacs Enterprise Mark II coring system) powered by a cordless electric drill. Salinity ice cores were stored in sterile U-Lines bags and transported back to the ship within 2 hours of sampling. Ice cores were stored in a -20°C walk-in freezer until processing. The ice cores were cut into sections of various lengths using a stainless steel, electric butcher band saw. The samples were placed in plastic cups with lids and melted at room temperature. Bulk salinity was measured on the melted water sample using a calibrated YSI 30 conductivity meter (practical salinity scale, unitless).The table contains the event label (1), time (2), and global coordinates (3,4) of each coring measurement. Each separate core has its local coordinates X (5) in [m] across the corresponding ridge transect (6). For each drill hole, the depth relative to the waterline of the top (7) and bottom (8) interface of each separate layer is given together with its salinity (9), isotope composition ID (10), and nutrient ID (11). The ice type (11) includes first-year ice (FYI), ridge, and ridge (water-filled) void. Each core has also measurements of the total ice thickness (12), ice draft (13), snow depth (14), and additional information on sampling (16). Photos of ice cores are additionally provided: doi:10.1594/PANGAEA.962537. Ice mass balance buoy SIMBA 2020T60 was installed at the Fort Ridge: doi:10.1594/PANGAEA.924269. Ridge thickness drilling was performed at Fort Ridge: doi:10.1594/PANGAEA.960347.