This datasheet includes radiocarbon measurement results of bulk organic matter from permafrost collected from the Lena Delta. Sediments were freeze-dried, ground, and weighed into silver boats, with sample sizes determined by TOC content to target 1 mg of organic carbon. Samples were acidified with three drops of 6 M HCl at 60 °C three times with one hour reaction time between treatments, then oven-dried overnight at 60 °C. Afterwards, acidified samples together with silver boats were folded into tin boats and converted into graphite targets using an elemental analyzer (Elementar vario Isotope) coupled to an automated graphitization system (Ionplus AG, AGE-3). Radiocarbon measurements were conducted using the MIni CArbon Dating System (MICADAS) accelerator mass spectrometer at Alfred Wegener Institute (AWI) (Mollenhauer et al., 2021).