Biochar is a solid by-product of biomass pyrolysis in an oxygen depleted atmosphere. It is reported that the use of biochar as a soil amendment has positive effects on soil chemical, physical and biological properties. A sorption/desorption kinetics experiments were conducted with the aim to study the effects of soil-biochar mixtures on the mobility of zinc (Zn). Sewage sludge and olive pomace-derived biochars as soil amendments were mixed with terra rossa soil, the most widespread soil type in the region of Istria. The results indicated that the adsorption of Zn in the mixture of studied soil with sewage sludge and olive pomace-derived biochars was not well-described by both Langmuir and Freundlich models. The highest Kd values which were measured at lower initial concentrations of Zn in sorption solution are caused by the presence of sorption sites with great selectivity which have relatively stronger bonding energy. Lower Kd values at higher initial concentrations of Zn in sorption solution may be explained by strong competition between heavy metals. Key soil properties that affect the Zn sorption in the soil are pH, clay mineral content and cation exchange capacity (CEC). Interactions between biochar and metals are complex and several sorption mechanisms are evident for divalent metals such as Zn, including electrostatic attraction with negatively charged biochar surfaces, complexation with biochar surface ligands and precipitation or co-precipitation with other mineral phases.