This application provides a method for performing onboarding. The method includes: A first core network device obtains first information, where the first information indicates that a terminal device performs onboarding, the first core network device is a core network device that serves the terminal device after the terminal device performs handover, and the first core network device supports an onboarding function. The first core network device performs onboarding on the terminal device based on the first information. According to the solutions of this application, after the terminal device performs handover, a core network device that serves the terminal device is the first core network device, and the first core network device supports the onboarding function. Therefore, according to the solutions of this application, the first core network device may continue to perform onboarding on the terminal device.