The Lawful Interception (LI) of communications is necessary in modern telecommunications networks in order to help law enforcement agencies with the investigation and prosecution of criminal activities. For IP networks that support user mobility, such as Mobile IP, the LI solution must be distributed throughout the network in order to satisfy the requirement that it capture 100% of a target user’s communications. This distribution is in conflict with another requirement which requires that the identity of the interception target remain unknown outside of the LI system: increasing the distribution of the LI solution to more nodes, as well as being inefficient, means that the identity of the target of the interception is more susceptible to being known via attacks, social engineering or unintentional misconfiguration. In this paper, we analyse LI solutions for Mobile IPv6 networks in terms their efficiency. We define an efficiency ratio which measures the balance between the requirement to capture 100% of target traffic and how distributed the efforts to intercept are. We examine the effect of alternative LI solutions on this measure through simulation. Our results show that a client driven approach which incorporates appropriate caching mechanisms provides a significant improvement in efficiency when compared to a traditional client/server approach.