Various examples pertaining to application of non-access stratum (NAS)-level congestion control timer values at intersystem change in mobile communications are described. A user equipment (UE) receives an indication of a NAS-level congestion control from a first type of wireless network. The UE starts a timer responsive to the receiving of the indication of the NAS-level congestion control. The UE then performs an intersystem change from the first type of wireless network to a second type of wireless network different from the first type by utilizing the timer.