Systems and methods are disclosed for performing online charging for text messages. One embodiment comprises a system that handles a Mobile Originated (MO) text message. The system receives a send request for the MO text message, and generates an online credit request for the MO text message. The system determines a type of originating network for the MO text message, and inserts an indicator of the originating network type in the online credit request. The system may also determine a type of terminating network for the MO text message, and insert an indicator of the terminating network type in the online credit request. The system then transmits the online credit request to an online charging system to charge for the MO text message.