A method and system for providing IP Multimedia Subsystem (IMS) session continuity to a User Equipment (UE) across a plurality of communication networks is provided. The UE traverses from a first communication network to a second communication network. A public user identity associated with a private user identity of the UE is registered with the first communication network by using a first address. The method includes generating (404) a complimentary private user identity associated with the public user identity. The method also includes obtaining (406) a second address from the second communication network when the UE traverses from the first communication network to the second communication network. Moreover, the method includes registering (408) the public user identity associated with the complimentary private user identity with the first communication network by using the second address.