Issues associated with the lack of promptness and accuracy of nondestructive testing (NDT) methods for determining the diffusion coefficient in thin porous materials are studied. Since the calibration of diffusant concentration transducers in a porous material takes a long time, the productivity of research on the diffusion coefficient is low when using conventional methods. The authors examine two methods enabling determination of the diffusion coefficient without the actual static characteristic of the used diffusant concentration transducer. The first method relies on recording the time point that corresponds to the maximum concentration of the diffusant following pulse application. When determining the target coefficient via the second method, it is possible to select two identical values of the transducer output characteristic following the pulse application with the recording of corresponding time points. The specified methods are compared. The errors in determining the target coefficient are studied under comparable conditions using both methods. The paper also analyzes the possibility of reducing the resulting error of Method II by selecting quantities included in the calculation expression. The study results can be useful in the production and use of items made of porous materials.