Dataset provides information about reactive silica (in mg Si L-1) in Lake Paione Superiore (LPS) at different layer depths along the water column within the period 1984-2013. Data are at least biannual (late summer/autumn). In total 283 records of reactive silica in the Lake for the period are uploaded. The range is from 0.14 to 0.82 mg Si L-1 (±0.105). Lake Paione Superiore is a high altitude Alpine lake, located in the Bognanco Valley, Piedmont Region, Italy. It has a surface area of 0.68 ha and a maximum depth of 11.5 m. The Lake is included in the monitoring sites of the UN-ECE Program ICP WATERS (International Cooperative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes)