A method for synchronizing welding currents of at least two welding current sources prior to performing a simultaneous welding process on at least one workpiece, in particular a welding process with non-consumable electrodes, wherein the method includes the following steps: a first welding current source outputting a reference signal, wherein the reference signal contains synchronization information; a second welding current source measuring or receiving the reference signal and evaluating the synchronization information contained in the reference signal; synchronizing a second welding current of the second welding current source with a first welding current of the first welding current source on the basis of the synchronization information. The invention furthermore relates to a welding current source and to a system having at least two welding current sources.