The synergistic effect of thiourea (TU) and p-phenylenediamine (PDA) additives in a thiosulfate-based bath is studied on the characteristics of silver coating on stainless steel-304. The synergistic effect arises from the enhanced combined impact of the additives compared to their individual contributions. The independent variables are optimized at concentrations of 40 g/L AgNO3, 40 g/L Na2S2O5, 200 g/L Na2S2O3, 0.6 g/L TU, and 0.5 g/L PDA, respectively. The process is conducted at a pH of 5.6 and a current density of 12.5 mA/cm² and at ambient temperature for 5-12 minutes. Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS), X-ray Diffraction (XRD), Tafel polarization, and Electrochemical Impedance Spectroscopy (EIS) are employed to characterize the silver coating. The TU additive acts as a brightener, leveling, and complexing agent, and PDA, functioning as a complexing, antioxidant, and stabilizing agent, resulted in increased thickness and reduced roughness. Under optimized conditions, thickness and roughness are approximately obtained 50 microns and 0.13 microns, respectively. Furthermore, the silver-coated stainless steel exhibited a 70% reduction in corrosion rate in 3.5% NaCl solution compared to the uncoated sample. Surface uniformity, smoothness, and glossiness of silver coating are enhanced, while roughness decreased, due to the reduced size of silver particles and improved filling properties.