As the registered owner of a SIM card, the individual or entity bears certain responsibilities. These include ensuring the SIM card is used lawfully and in accordance with the terms and conditions set by the telecom service provider. The owner is also responsible for any charges or fees incurred through the use of the SIM card, including data usage, calls, and messages. In cases of misuse or illegal activities conducted via the SIM card, the owner could be held accountable, depending on the jurisdiction.