The adsorption mechanism of activated carbon toward copper and gold thiosulfate complexes was investigated. Both adsorption kinetics of copper and gold thiosulfate complexes onto activated carbon conform to the pseudo‐second‐order model. The adsorption isotherm of activated carbon toward the copper thiosulfate complex is in accordance with the Freundlich model, while that of the gold thiosulfate complex fits the Langmuir model. The bonding characteristics of the loaded carbon suggest that the adsorption mechanism of copper thiosulfate is different from that of gold thiosulfate. The adsorption capacity of the activated carbon toward copper reaches 79.04 mg/g under the experimental conditions, which is approximately two orders of magnitude higher than that of gold. This implies that the use of activated carbon for gold recovery from thiosulfate leachate may face great challenges due to the low adsorption capacity of gold, as well as the competitive adsorption of copper and thiosulfate.