Mexican authorities have issued a warning regarding a growing black market for mobile phone SIM cards. This illicit trade allows individuals to acquire chips already linked to other people’s identities, potentially circumventing new registration requirements. The government is mandating all mobile phone users to register their lines by June 30th to combat crime and improve security. As of April, registration rates were reported as low, raising concerns about widespread non-compliance. The availability of pre-registered SIM cards on the black market complicates enforcement efforts and poses a risk of identity theft. Authorities are actively addressing the issue to ensure the registration process is secure and effective. The practice was observed in central Mexico City.