Herein, we report a series of 5d transition metal (TM) single atoms supported on ZIS as promising catalysts for the hydrogen evolution reaction using first-principles calculations. The binding behaviors of TMs with the ZIS surface in single-atom catalyst formation are analysed using the adsorption energy (Eads), partial density of states (PDOS), charge density difference (CDD), and crystal orbital Hamilton population (COHP). The TM@ZIS (TM = Ta, W, Re, Os, Ir, and Pt) shows excellent hydrogen evolution performance with the Gibbs free energy (ΔGH*) values from -0.120 to 0.128 eV. The Tafel and Heyrovsky reaction mechanisms to drive H2 formation are also identified.