Disclosed herein are techniques and systems for tracking assets using wireless beacons attached to the assets. In some embodiments, an asset tracking system may receive, from a mobile device, a device identifier (ID) of a wireless beacon. At a different time, the asset tracking system may receive, from the mobile device, event data indicating that the mobile device is located at a site among a plurality of sites maintained in a data store. The asset tracking system may determine whether a time between the receiving of the device ID and the receiving of the event data is less than a threshold amount of time, and, if so, the asset tracking system may associate the wireless beacon to the site.