The diffusion coefficient of Li-ions (D Li + ) within carbon-rich silicon-oxycarbide ceramic anodes of specific chemical composition SiO0.95C3.72 is determined by potentiostatic and galvanostatic intermittent titration technique (PITT, GITT) and electrochemical impedance spectroscopy (EIS). The estimated values for D Li + range between 10−9 and 10−11 cm2 s−1, dependent on the applied method. The observed variation of D Li + is in a comparable range as reported for disordered carbons, well reflecting the Li-ion storage in the segregated free carbon phase in the amount of about 43 wt-% within the SiOC microstructure. However, in contrast to graphite and disordered carbons, the diffusion coefficient of lithium within carbon-rich SiOC is less potential dependent. This feature is discussed with respect to the particular morphology of the free carbon phase.