Methods, systems and devices are provided for automatically linking a device to an activity tracking device. One method includes obtaining, at the device, a semi-unique identifier from a website. The semi-unique identifier is for an activity tracker that has been paired to a user account of the website. The method includes scanning, by the device, for the semi-unique identifier. The scanning is of advertising messages generated by one or more activity trackers. The method identifies the activity tracker by matching the advertised semi-unique identifier to the semi-unique identifier obtained from the website. The method then includes establishing a link between the activity tracker and the device. The link is established without requiring user initiation to link the activity tracker to the device.