This paper classifies invariant surfaces in the 3-dimensional solvable Lie group \(\text {Sol}_3\) that act as solitons under the Gauss curvature flow. Specifically, we consider solitons associated with the canonical basis of Killing vector fields \(\{F_1, F_2, F_3\}\) , where \(F_1\) and \(F_2\) generate horizontal translations and \(F_3\) generates a scaling isometry. Rigidity results are established for \(F_3\) -invariant surfaces, proving that certain totally geodesic vertical planes are the only \(F_1\) - and \(F_2\) -solitons. Finally, for \(F_1\) -invariant surfaces, we describe the main geometric properties of \(F_2\) - and \(F_3\) -solitons, considering both extrinsic and intrinsic Gauss curvatures.