Apparatuses, methods, and systems are disclosed for mobility management among multiple network slices. One apparatus includes a processor that receives a mobility management request from the mobile unit and forwards the mobility management request to the secondary network slice. Here, the mobile unit is simultaneously served by the primary network slice and a secondary network slice of the mobile communication network. The apparatus sends a single mobility management response to the mobile unit, wherein the single mobility management response includes a first response from the primary network slice and a second response from the secondary network slice. In various embodiments, the apparatus may include a network interface for communicating over a mobile communication network.