Recycled Numbers, Residual Identities: SIM Reassignment, Data Protection and Regulatory Accountability in Nigeria

Mobile telephone numbers now mediate access to banking, messaging, account recovery, public services and a growing range of data driven systems. Their reassignment after inactivity is commonly treated as a routine aspect of telecommunications administration. This article argues that reassignment creates a distinct category of legal and governance risk, described here as digital identity residuality. A number may cease to belong to one subscriber while remaining embedded in that subscriber’s financial, social and institutional relationships. The resulting exposure arises through a chain of decisions distributed across mobile network operators, banks, platforms, identity systems and regulators.The article develops a critical legal account of this problem in Nigeria, with Airtel Nigeria treated as an illustrative operator case. It combines Restricted Access Limited Control theory, contextual integrity, multilevel information privacy management, regulatory space theory and competition analysis. These perspectives show why number reassignment cannot be understood only as a private contractual event or a consumer education problem. It is an infrastructure governance issue involving the control, circulation and continuing social meaning of an identifier.The article examines the Nigeria Data Protection Act 2023, the Nigerian Communications Act 2003, the Nigerian Communications Commission’s subscriber and competition rules, and the emerging Telecoms Identity Risk Management System. It argues that the present framework recognises elements of the problem while leaving a material lifecycle gap between a number’s deactivation and its safe reuse across sectors. It further considers how the issue will deepen as smart city systems and artificial intelligence rely on mobile numbers for identity resolution, automated decision making and service coordination. The article proposes a Reassignment Safety Protocol and a joint NCC and NDPC Number Lifecycle Code. These reforms would establish advance warning, a safety interval, cross sector status verification, auditability, meaningful remedies and special safeguards for financially and socially embedded numbers.The central claim is that mobile number governance has become a core form of digital identity governance. Nigerian law should regulate the full life of the identifier accordingly.