Sandwich packings are innovative separating column internals based on a periodic arrangement of two conventional structured packings with different geometrical surface areas. They are operated with partially flooded layers to intensify phase interactions and enhance mass transfer. The application of sandwich packings in absorption and distillation processes requires detailed understanding of the gas–liquid mass transfer phenomena in the individual layers. For this reason, we carried out an experimental investigation of CO₂ desorption and developed an additive approach to process the measured data. On this basis, liquid-side mass transfer correlations for the flow patterns in the flooded packings sections were derived. The novel additive approach together with the developed correlations allows accurate prediction of the liquid-side mass transfer in sandwich packings.