Various solutions for avoiding circuit-switched call drop with respect to user equipment and network apparatus in mobile communications are described. An apparatus may transmit a non-access stratum (NAS) message in a NAS signaling connection. The apparatus may receive a NAS response message. The apparatus may initiate a timer to control the NAS signaling connection. The apparatus may further receive a circuit-switched (CS) service notification. The apparatus may stop the timer and execute a CS service procedure.