The electron mobility and concentration in double-gate silicon-on-insulator (SOI) gate-all-around transistors is extracted by Hall effect measurements at room and liquid nitrogen temperature. The Hall mobility is compared with the drift mobility determined from the transconductance measurement of the devices in strong inversion. The results of this study indicate that the method based on I-D/(g(m))(0.5) provides acceptable values for the drift mobility. The experiment reveals high carrier mobility dominated at room temperature by a phonons scattering mechanism and at low temperature by mixed scattering processes, with a predominance of the surface roughness scattering mechanism. No evidence was found for special transport mechanisms induced by volume inversion in relatively thick SOI films.