This work explores the adsorption and permeation of chemical warfare agents on polymer coatings to assess their protective potential. Two highly cross-linked aliphatic polyurethanes (PUs) were synthesized from two diisocyanate trimers, and their adsorption and permeation of dimethyl methylphosphonate (DMMP) and 2-chloroethyl ethyl sulfide (CEES) were analyzed using quartz crystal microbalance with dissipation and gas chromatography. The study revealed distinct adsorption properties for each agent and the PU. CEES, with higher polarity, exhibited greater readsorption compared to DMMP. IPtri-PU (alicyclic structure) showed negligible desorption and resorption, resulting in minimal permeation, unlike Htri-PU (aliphatic structure). Thus, alicyclic PUs are more promising for reducing adsorption and permeation.