Systems and methods are disclosed for supporting, in a device, Wireless Local Area Network (WLAN)-Wireless Wide Area Network (WWAN) mobility, data offload, and simultaneous usage of different access networks on a per Access Point Name (APN) basis. The device determines an access network among WWAN and WLAN for a data stream having an APN. The device additionally hands off the data stream according to the determined access network, while maintaining Internet Protocol (IP) continuity. The device further routes packets of the data stream to at least one of a protocol stack or interface for the determined access network in accordance with an inter-system routing policy (ISRP).