This paper presents a novel scheme that enables IPv6 mobile networks to perform optimal route optimization. The proposed scheme exploits features of the widely deployed border gateway protocol (BGP). When a mobile network is about to change its point of attachment to the Internet, its mobile router (MR) gets a new care-of-address (CoA) from the visited location and sends a binding update to its home agent (HA). Additionally, MR gets a new temporary network prefix (TNP) at the new location using the prefix delegation protocol. MR then advertises this TNP to its subnet via a router advertisement (RA) message and enables the mobile network nodes (MNNs) to build their own respective CoAs. Simultaneously, this TNP is also sent to the border router (BR) of the home network to enable BR update its BGP routing table. This operation is performed to build an association between the TNP and the mobile network prefix (MNP). BR then notifies its peers of this new update. This procedure will enable any correspondent node (CN) to directly communicate with MNNs, avoiding therefore ingress filtering and reducing both signaling and processing overhead on MR and the home agent (HA). A comparison of the proposed scheme against the NEMO Basic Support scheme, in terms of communication delay, is made via a simple performance analysis.