Embodiments are directed towards SMS-initiated mobile registration. A mobile device sends an SMS message to a mobile registration device. In response, the mobile registration device generates a random identifier and associates it with the mobile device identifier of the mobile device. Then, the mobile registration device sends a response SMS message to the mobile device, the response SMS message containing a Uniform Resource Identifier (URI) to a mobile registration web page, where the URI contains the generated random identifier. The mobile device uses the URI to navigate to the mobile registration web page, where additional registration information is provided. The mobile registration device associates the additional registration information with the mobile device based on the generated random identifier included in the URI, and creates a user account based on the mobile number from which the SMS message was received and the additional registration information.