A method and system for dynamic selection of user plane or control plane signaling for mobile station location determination. A positioning system receives a request for the location of a mobile station and then makes a determination, based on one or more factors, of whether to employ user plane signaling or control plane signaling to obtain mobile station location data. The factors may include mobile station capability, mobile station call state, mobile station support for user plane signaling, mobile station support for simultaneous voice and data communication, time, precision of requested location, subscriber preference, failure of control plane or user plane signaling, and preference specified by the request, among others. Given the determination, the positioning system then employs the selected signaling mechanism.