Systems and methods for selecting offline charging functions per service data flow during a data session over a packet data network. One embodiment comprises a Policy and Charging Rules Function (PCRF) that receives information regarding service data flows initiated during a data session over a packet data network. For each of the service data flows, the PCRF selects an offline charging function for the service data flow based on the information for the service data flow, and provides an identifier for the selected offline charging function to a Policy and Charging Enforcement Function (PCEF). The PCEF may then generate charging requests for the service data flow in response to chargeable events, and route the charging requests to the selected offline charging function based on the identifier.