Method and apparatus for providing Mobile internet protocol (IP) service through a network address translation gateway. In one example, a gateway between a local area network (LAN) and a wide area network (WAN) is provided. A foreign agent (FA) module is configured to advertise a care-of address (CoA) on the LAN and process registration and mobile IP communication traffic on the LAN and the WAN side of the gateway. A control module is configured to identify the registration and the mobile IP communication traffic on the LAN and the WAN. The control module sends mobile IP traffic to the FA and other traffic to a network address translation (NAT) module. In this manner, network address translation of mobile IP traffic is advantageously omitted. This allows the IP-in-IP tunnels used by mobile IP to pass through the gateway.