A method for migration from a subscriber identity module (SIM) card to an embedded universal integrated circuit card (eUICC), a device, and a system, where the method includes receiving a first migration instruction from a user, where the first migration instruction instructs to migrate from a SIM card to an eUICC, sending a first request to a server, where the first request includes a user identity corresponding to the SIM card and an identity of the eUICC such that the server generates or selects a profile for the eUICC according to the user identity, downloading the profile from the server to the eUICC, enabling the profile, accessing a mobile network using the profile, and disconnecting a session from the SIM card. The solution resolves a requirement that a user of a compatible terminal needs to implement migration from a SIM card to an eUICC during a transition period.