City Logistics aims to achieve higher levels of consolidation in vehicles that typically requires exchanging loads at intermediate locations. Swapping goods between retail stores in urban areas due to stock shortages is a common problem arising in for example, omni-channel logistics. This study develops a two-stage stochastic program for designing a product swap network. The upper stage of the program deals with the strategic decision of locating transhipment nodes, while the lower stage finds the optimal operational vehicle routing solution. Uncertainties in demand, traffic conditions, and vehicle loading efficiency are considered. Numerical studies evaluate various solution procedures and demonstrate the importance of considering stochasticity and the value of the two-stage model.