Techniques for IP flow mobility in a wireless data communications system, which allow for selective movement of IP data flows between different access networks supporting different access technology types. An access terminal (AT) is configured to selectively communicate using plural access technologies. Plural IP data flows are established between the AT and a first access network using a first technology type. A flow mobility trigger condition is detected, and in response, at least one IP data flow is moved to a second access network using a second technology, while maintaining at least another of the data flows to the first access network, and using the same IP address for the AT for data flows handled by both access networks, by using a mapping function between packet-filters for data flows and the access technology. The techniques may be used in conjunction with IP mobility protocols such as PMIP and CMIP.