The details of an apparatus and method for determining uplink ciphering activation time in universal mobile telecommunications system user equipment are disclosed herein. The ciphering activation time is determined for radio bearers other than RB2 by measuring the data rate on each target radio bearer during the time that it takes for a polling or RRC message sent from the user equipment UE to be acknowledged by the network UTRAN. For RB2, the uplink ciphering activation time is determined by taking into account the size of the RRC response message and the data already queued on RB2 for transmission.