IPv6 over Low power Wireless Personal Area Networks (6Lo-WPAN) is a protocol architecture that has recently been ratified to enable the seamless interconnection of wireless sensor networks (WSN) to the Internet. This opens up a wealth of application opportunities as well as a number of difficult challenges. One of these challenges is the efficient support of sensor mobility. In order to provide mobility for sensor nodes, this paper proposes a mobility support scheme for IPv6 over Low power Wireless Personal Area Network (6LoWPAN) sensor nodes. We define a new protocol, named Fast Handover for Sensor PMIPv6 (FPMIPv6-S), which supports global IP mobility for 6LoWPAN mobile sensor nodes. We present a performance comparison of PFMIPv6 and FPMIPv6-S using an analytical approach. Performance results show that our proposed scheme exhibits a lower handoff latency, thus extending the network lifetime.