Systems, methods, and software for selecting among a plurality of IMS network slices. When an IP Multimedia Subsystem (IMS) network is partitioned into a plurality of IMS network slices, an IMS slice selection manager may be implemented at an edge of the IMS network slices. The IMS slice selection manager receives an IMS slice selection policy, and receives an IMS service request for an IMS service. The IMS slice selection manager selects an IMS network slice to provide the IMS service based on the IMS slice selection policy, and causes routing of the IMS service request to the selected IMS network slice.