In this letter the expression of the phase time is derived for a two‐dimensional coherent wave packet traveling through a generic mesoscopic system. The obtained analytical expression generalizes the definition of phase time for a single one‐dimensional scattering state to the case of coherent transport through two‐dimensional multichannel mesoscopic structures, and results in a suitable average of the single‐mode phase times. As an application, numerical results for a quantum wire and a double‐barrier resonant‐tunneling diode with and without an ionized impurity are also presented. ©1996 American Institute of Physics.