This data set is part of a larger data harmonization effort to make lake sediment core data machine readable and comparable. Here we standardized grain-size data of sediment core PG1972, retrieved in 2009 from Lake Bezrybnoe (Lena Delta, Russia) at 4.7 m water depth. The thermokarst lake Bezrybnoe is small basin in tundra region and has one outflow and three inflows. It lies at an elevation of ca. 6 m a.s.l. with a surface area of ca. 0.77 km2 and a maximum lake water depth of estimated 5.3 m. The 1.08 m sediment core was retrieved by a UWITEC hammer action gravity corer (60mm) during the RU-Land_2009_Lena-transect expedition of the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI, Germany, Potsdam) in cooperation with the North Eastern Federal State University (NEFU, Russia, Yakutsk). Grain-size was measured by laser-based particle sizing (COULTER LS 200 Laser Diffraction Particle Analyser) at AWI Potsdam.